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Sample records for binary near-earth asteroid

  1. The cool surfaces of binary near-Earth asteroids

    OpenAIRE

    Delbo, Marco; Walsh, Kevin; Mueller, Michael; Harris, Alan W.; Howell, Ellen S.

    2011-01-01

    Abstract Here we show results from thermal-infrared observations of km-sized binary Near-Earth Asteroids (NEAs). We combine previously published thermal properties for NEAs with newly derived values for three binary NEAs. The ?value derived from the Near-Earth Asteroid Thermal Model (NEATM) for each object is then used to estimate an average thermal inertia for the population of binary NEAs and compared against similar estimates for the population of non-binaries. We find that thes...

  2. The Cool Surfaces of Binaries Near-Earth Asteroids

    NARCIS (Netherlands)

    Delbo, Marco; Walsh, K.; Mueller, M.

    2008-01-01

    We present results from thermal-infrared observations of binary near-Earth asteroids (NEAs). These objects, in general, have surface temperatures cooler than the average values for non-binary NEAs. We discuss how this may be evidence of higher-than-average surface thermal inertia. The comparison of

  3. Biases affecting radar detection of binary near-Earth Asteroids

    Science.gov (United States)

    Benner, Lance A. M.; Brozovic, Marina; Naidu, Shantanu P.

    2016-10-01

    Radar observations at Arecibo and Goldstone provide a powerful tool for the discovery, characterization, and orbit estimation of binary near-Earth asteroids (NEAs). To date, 73% of binary and triple NEA systems have been discovered by radar and 87% have been detected by radar. Here we describe biases not discussed in detail in the peer-reviewed literature that can adversely affect radar detection of NEA satellites. In a Doppler-only echo power spectrum, most NEA binaries have a rapidly-spinning primary that appears as a broad echo, and a slowly orbiting, tidally-locked companion that appears as a narrow spike superimposed on the primary echo. The most important factor for detection of a companion is the signal-to-noise ratio (SNR), which is proportional to (r -4)(D 3/2)(P 1/2), where r is the distance, D is the diameter, and P is the rotation period. Low SNRs occur primarily due to the distance, a small diameter, and rapid rotation and necessitate coarse frequency resolution that limits detection of narrow spikes. Spikes in echo power spectra also occur due to glints, self noise, and radar albedo features, so confirmation of a binary requires delay-Doppler images that show two separate echoes whose positions change with time. Most companions appear tidally locked, but ~25% rotate more rapidly than their orbital periods. For example, in October 2001 the companion of 1998 ST27 was not obvious in echo power spectra or in single delay-Doppler images but was seen only when all the images from each day were summed, revealing a trail of faint pixels. The satellite SNRs were weak because its rotation is much more rapid than its orbital period. Other important factors include differences between the bandwidth of the companion and the Doppler resolution; weak SNRs due to a small diameter; self noise due to a small number of Fourier transforms; rapid orbital motion that decreases the SNR of the satellite into the noise; failure to inspect the data at sufficiently high Doppler

  4. Some Dynamic Characteristics of Binary Near-Earth Asteroids

    Directory of Open Access Journals (Sweden)

    Ivanenko, N.V.

    2017-01-01

    Full Text Available Tidal acceleration exerted by the terrestrial planets and Jupiter’s are determined, orbital resonances to evaluate the motion stability in binary asteroid systems are calculated. Radius of the Hill sphere surrounding the main component in approximation of the planetary three-body problem — the Sun-main component-satellite is calculated. Escape velocities from the surface of the asteroid satellites are found and the conclusion on the possibility of substance loss is made.

  5. Physical Characterization and Origin of Binary Near-Earth Asteroid (175706) 1996 FG3

    NARCIS (Netherlands)

    Walsh, Kevin J.; Delbo', Marco; Mueller, Michael; Binzel, Richard P.; DeMeo, Francesca E.

    2012-01-01

    The near-Earth asteroid (NEA) (175706) 1996 FG3 is a particularly interesting spacecraft target: a binary asteroid with a low-Δv heliocentric orbit. The orbit of its satellite has provided valuable information about its mass density while its albedo and colors suggest it is primitive or part of the

  6. Physical Characterization and Origin of Binary Near-Earth Asteroid (175706) 1996 FG3

    NARCIS (Netherlands)

    Walsh, Kevin J.; Delbo', Marco; Mueller, Michael; Binzel, Richard P.; DeMeo, Francesca E.

    2012-01-01

    The near-Earth asteroid (NEA) (175706) 1996 FG3 is a particularly interesting spacecraft target: a binary asteroid with a low-Δv heliocentric orbit. The orbit of its satellite has provided valuable information about its mass density while its albedo and colors suggest it is primitive or part of the

  7. Active Near Earth Asteroids

    Science.gov (United States)

    Jenniskens, Peter

    2015-08-01

    Past activity from Near Earth Asteroids is recorded in the meteoroid streams that cause our meteor showers. Automated meteoroid orbit surveys by photographic, low-light video, specular radar, and head-echo radar reflections are providing the first maps of meteor shower activity at different particle sizes. There are distinct differences in particle size distributions among streams. The underlaying mechanisms that created these streams are illuminated: fragmentation from spin-up or thermal stresses, meteoroid ejection by water vapor drag, and ejection of icy particles by CO and CO2 sublimation. The distribution of the meteoroid orbital elements probe the subsequent evolution by planetary perturbations and sample the range of dynamical processes to which Near Earth Asteroids are exposed. The non-stream "sporadic" meteors probe early stages in the evolution from meteoroid streams into the zodiacal dust cloud. We see that the lifetime of large meteoroids is generally not limited by collisions. Results obtained by the CAMS video survey of meteoroid orbits are compared to those from other orbit surveys. Since October 2010, over 200,000 meteoroid orbits have been measured. First results from an expansion into the southern hemisphere are also presented, as are first results from the measurement of main element compositions. Among the many streams detected so far, the Geminid and Sextantid showers stand out by having a relatively high particle density and derive from parent bodies that appear to have originated in the main belt.

  8. Radar observations and physical modeling of binary near-Earth asteroid (1862) Apollo

    Science.gov (United States)

    Ford, Thomas F.; Benner, Lance A.; Brozovic, Marina; Leford, Bruce; Nolan, Michael C.; Giorgini, Jon D.; Ostro, Steve J.; Margot, Jean-Luc

    2014-11-01

    Binary asteroid 1862 Apollo has an extensive observational history allowing many of its characteristics to be investigated. Apollo was one of the first objects to show evidence for the YORP effect (Kaasalainen et al. 2007, Nature 446, 420) and its mass has been estimated by detection of the Yarkovsky effect (Nugent et al. 2012, AJ 144, 60; Farnocchia et al. 2013, Icarus 224, 1). We observed Apollo at Arecibo and Goldstone from Oct. 29-Nov. 13, 2005, obtaining a series of echo power spectra and delay-Doppler images that achieved resolutions as high as 7.5 m/pixel. The Arecibo images show that Apollo is a binary system with a rounded primary that has two large protrusions about 120 deg apart in longitude. We used the Arecibo data and published lightcurves to estimate the primary's 3D shape. Our best fit has major axes of ~1.8x1.5x1.3 km and a volume of ~1.6 km^3. The protrusions have lengths of ~300 and 200 m, are on the primary's equator, and give Apollo a distinctly different appearance from the primaries with equatorial ridges seen with other binary near-Earth asteroids. We estimated the pole by starting with the Kaasalainen et al. spin vector of ecliptic (longitude, latitude)=(50 deg, -71 deg) +- 7 deg and letting it float. Our best fit has a pole within 11 deg of (longitude, latitude)=(71, -72). Convex models produced from inversion of lightcurves by Kaasalainen et al. and thermal infrared data by Rozitis et al. (2013, A&A 555, A20) are more oblate than our model, do not show protrusions, and have somewhat different pole directions. The Arecibo images reveal weak but persistent echoes from a satellite on Nov. 1 and 2 but cover only a fraction of its orbit. The images are insufficient to estimate the satellite's shape and yield a rough estimate for its long axis of 190 m. Preliminary fits give an orbital period of ~27.0-27.5 h and a semimajor axis of ~3.5-4.0 km, implying a mass of 2.8-3.9E12 kg and a bulk density of 1.7-2.4 g/cm^3. The density is consistent with

  9. Radar Shape Modeling of Binary Near-Earth Asteroid 2000 CO101

    Science.gov (United States)

    Jimenez, Nicholas; Howell, E. S.; Nolan, M. C.; Taylor, P. A.; Benner, L. A. M.; Brozovic, M.; Giorgini, J. D.; Vervack, R. J.; Fernandez, Y. R.; Mueller, M.; Margot, J.; Shepard, M. K.

    2010-10-01

    We observed the near-Earth binary system 2000 CO101 in 2009 September using the Goldstone and Arecibo radar systems and inverted these images to create shape models of the primary. Asteroid 2000 CO101 was discovered to be a binary system from Arecibo images taken on 2009 September 26 (Taylor et al. 2009). Analyzing the images, we were able to determine approximate values for the radius of the primary (310 m) and the radius of the secondary (22 m). The maximum observed range separation was approximately 610 m. The images show it to appear spherical. Shape modeling of the primary of this system will constrain the asteroid's size, spin rate, and pole orientation. Because other NEA binary systems have exhibited shapes similar to that of 1999 KW4 (Ostro et al. 2006, Scheeres et al. 2006), we initially adopted this shape for 2000 CO101 and have allowed only the linear scales along the three principal axes to adjust to the radar data. This enables us to constrain the volume. With some constraints on the orbit of the satellite we will place limits on the density of the primary. The near-infrared spectrum of 2000 CO101 was measured on 2009 September 21 and 2010 March 13. The 0.8-2.5 micron spectrum was measured on both dates, and shows a featureless, red-sloped spectrum. On September 21 we also measured the thermal emission between 2-4 microns to determine the albedo and thermal properties. Both standard thermal models and thermophysical models have been applied to these data. The albedo we derive from the thermal modeling must also be consistent with the radar size. Characterization of this unusual NEA binary system will be presented.

  10. Shape model of the binary near-Earth asteroid (285263) 1998 QE_2

    Science.gov (United States)

    Springmann, A.; Taylor, P.; Nolan, M.; Howell, E.; Benner, L.; Brozović, M.; Giorgini, J.; Busch, M.; Margot, J.; Lee, C.; Gao, J.

    2014-07-01

    Binary systems comprise ˜1/6 of the near-Earth object population larger than 200 meters in diameter, providing important clues to asteroids' masses and densities. On May 31, 2013, the binary near-Earth-asteroid system (285263) 1998 QE_2 had a 0.04-au close approach to the Earth. We observed the binary system from May 30 to June 27 with the Goldstone Solar System Radar (which discovered the system's binary nature, operating at 3.5 cm / 8.56 GHz) and Arecibo Observatory planetary radar system (operating at 12.6 cm / 2.38 GHz). The size of the QE_2 primary and the short light travel time afforded us an excellent data set of high resolution delay-Doppler images as fine as 7.5 meters/pixel of this asteroid and its moon. We used the extensive radar dataset to fit 3D shape models for both primary and secondary using a nonlinear iterative inverse process [1,2]. A preliminary scale model for both system components is shown in the figure. The preliminary primary model is a roughly spherical body, 3.2 ± 0.3 km in effective diameter. Some radar-bright spots in the delay-Doppler images may be indicative of boulders. Lightcurve data show a rotation period of 4.749 ± 0.002 h for the primary [3]. The best fit to a subset of radar data suggests a prograde pole at (119°, +35°) in ecliptic coordinates [4]. The secondary model indicates an effective diameter of 800 ± 80 m (for a primary:secondary diameter ratio of ≈4:1) for an elongated object with a concavity on one side of the long axis. The secondary is in a tidally locked spin state with an orbital period of 31.31 ± 0.01 h hours derived from radar, and a semimajor orbital axis of 6.2 ± 0.1 km (approximately quadruple the radius of the primary). The orbit is approximately circular (e Earth-asteroid binary-system orbits. We assume that the primary and secondary poles are aligned with the best-fit mutual-orbit pole. All orbital parameters were derived from radar data. From orbital fits, we estimate the system mass to be 1

  11. Thermophysical Modeling of Contact Binary Near-Earth Asteroid 1996 HW1

    NARCIS (Netherlands)

    Magri, C.; Howell, E. S.; Nolan, M. C.; Taylor, P. A.; Fernández, Y. R.; Mueller, M.; Rivkin, A. S.; Vervack, R. J., Jr.

    2011-01-01

    Near-Earth asteroid (8567) 1996 HW1 was observed spectroscopically at 1.9-4.0 microns during August- October 2008 using the SpeX instrument at NASA's Infrared Telescope Facility (IRTF). These spectra are being modeled using a new thermophysical program that accounts for the object's spin orientation

  12. Thermophysical Modeling of Contact Binary Near-Earth Asteroid 1996 HW1

    NARCIS (Netherlands)

    Magri, C.; Howell, E. S.; Nolan, M. C.; Taylor, P. A.; Fernández, Y. R.; Mueller, M.; Rivkin, A. S.; Vervack, R. J., Jr.

    2011-01-01

    Near-Earth asteroid (8567) 1996 HW1 was observed spectroscopically at 1.9-4.0 microns during August- October 2008 using the SpeX instrument at NASA's Infrared Telescope Facility (IRTF). These spectra are being modeled using a new thermophysical program that accounts for the object's spin orientation

  13. Dynamics of Binary Near-Earth Asteroid System (35107) 1991 VH

    Science.gov (United States)

    Naidu, Shantanu P.; Margot, J. L.; Busch, M. W.; Taylor, P. A.; Nolan, M. C.; Howell, E. S.; Giorgini, J. D.; Benner, L. A. M.; Brozovic, M.; Magri, C.

    2012-05-01

    Near-Earth Asteroid (35107) 1991 VH was discovered to be a binary in March 1997, based on its light-curve (IAUC 6607). It made a very close approach to the Earth in August 2008 at a distance of 0.045 AU. We used this opportunity to secure an extensive radar data set with the Arecibo S-band (2380 MHz, 13 cm wavelength) planetary radar system, including range-Doppler images with spatial resolution as fine as 15 m. The images (spanning 14 days) reveal that the primary is roughly spheroidal with a radius of 650 m. The range extent of the secondary in these images varies from less than 100 m to more than 200 m indicating that it is highly elongated. The radar data provide an excellent determination of the mutual orbit: The orbital period is 32 hours, the eccentricity is 0.05, and the total system mass is 1.5e12 kg. Numerical simulations of the spin of the elongated secondary in this eccentric mutual orbit reveal a large region of chaos in the phase space, similar to that observed in Saturn’s moon Hyperion (Wisdom, Peale, Mignard 1984). The chaotic region surrounds the 1:2, 1:1, 3:2 and 2:1 spin-orbit resonances, but allows for islands of stability around the 1:2 and 1:1 spin-orbit states. The secondary’s echo bandwidths indicate that its spin rate indeed lies within or very close to this chaotic region. To date no acceptable fit to the sequence of secondary images has been found under the assumption of synchronous spin. Saturn’s moon Hyperion is the only solar system object known so far to have a chaotic spin state (Wisdom, Peale, Mignard 1984).

  14. Radar imaging of binary near-Earth asteroid (357439) 2004 BL86

    Science.gov (United States)

    Benner, Lance A. M.; Brozovic, Marina; Giorgini, Jon D.; Taylor, Patrick A.; Howell, Ellen S.; Busch, Michael W.; Nolan, Michael C.; Jao, Joseph S.; Lee, Clement G.; Ford, H. Alyson; Ghigo, Frank D.

    2015-11-01

    We report radar imaging of near-Earth asteroid 2004 BL86 obtained at Goldstone, Arecibo, Green Bank, and elements of the Very Long Baseline Array between 2015 January 26-31. 2004 BL86 approached within 0.0080 au on January 26, the closest known approach by any object with an absolute magnitude brighter than ~19 until 2027. Prior to the encounter, virtually nothing was known about its physical properties other than its absolute magnitude of 19, which suggested a diameter within a factor of two of 500 m. 2004 BL86 was a very strong radar target that provided an outstanding opportunity for radar imaging and physical characterization. Delay-Doppler images with range resolutions as fine as 3.75 m placed thousands of pixels on the object and confirmed photometric results reported by Pravec et al. (2015, CBET 4063) that 2004 BL86 is a binary system. During the observations, the asteroid moved more than 90 deg and provided a range of viewing geometries. The bandwidth was relatively narrow on Jan. 26, reached a maximum on Jan. 27, and then narrowed on Jan. 28, a progression indicating that the subradar latitude moved across the equator during those days. The images reveal a rounded primary with an equatorial diameter of ~350 m, evidence for ridges, possible boulders, and a pronounced angular feature ~100 m in diameter near one of the poles. Images from Jan. 26 show arcs of radar-bright pixels on the approaching and receding limbs that extend well behind the trailing edge in the middle of the echo. This is the delay-Doppler signature of an oblate shape seen at least a few tens of degrees off the equator. A rough estimate for the diameter of the secondary is ~70 m and its narrow bandwidth is consistent with the 14-h orbital period reported by Pravec et al. (2015). The images are suitable for 3D shape, pole, orbit, and mass estimation. The observations utilized new data taking equipment at Green Bank to receive X-band (8560 MHz, 3.5 cm) transmissions from the 70 m DSS-14

  15. The binary near-Earth asteroid (175706) 1996 FG3 - An observational constraint on its orbital stability

    CERN Document Server

    Scheirich, P; Jacobson, S A; Ďurech, J; Kušnirák, P; Hornoch, K; Mottola, S; Mommert, M; Hellmich, S; Pray, D; Polishook, D; Krugly, Yu N; Inasaridze, R Ya; Kvaratskhelia, O I; Ayvazian, V; Slyusarev, I; Pittichová, J; Jehin, E; Manfroid, J; Gillon, M; Galád, A; Pollock, J; Licandro, J; Alí-Lagoa, V; Brinsfield, J; Molotov, I E

    2014-01-01

    Using our photometric observations taken between April 1996 and January 2013 and other published data, we derive properties of the binary near-Earth asteroid (175706) 1996 FG3 including new measurements constraining evolution of the mutual orbit with potential consequences for the entire binary asteroid population. We also refined previously determined values of parameters of both components, making 1996 FG3 one of the most well understood binary asteroid systems. We determined the orbital vector with a substantially greater accuracy than before and we also placed constraints on a stability of the orbit. Specifically, the ecliptic longitude and latitude of the orbital pole are 266{\\deg} and -83{\\deg}, respectively, with the mean radius of the uncertainty area of 4{\\deg}, and the orbital period is 16.1508 +\\- 0.0002 h (all uncertainties correspond to 3sigma). We looked for a quadratic drift of the mean anomaly of the satellite and obtained a value of 0.04 +\\- 0.20 deg/yr^2, i.e., consistent with zero. The drif...

  16. Spacecraft orbit lifetime within two binary near-Earth asteroid systems

    Science.gov (United States)

    Damme, Friedrich; Hussmann, Hauke; Oberst, Jürgen

    2017-10-01

    We studied the motion of medium-sized and small spacecraft orbiting within the binary asteroid systems 175,706 (1996 FG3) and 65,803 Didymos (1996 GT). We have considered spacecraft motion within the binary systems distance regimes between 0.4 and 2.5 km for Didymos and 0.8-4 km for 1996 FG3. Orbital motion of spacecraft, beginning from 20,000 initial conditions lying in the orbital planes of the secondary, were simulated and evaluated for lifespan. The simulations include the effects of (1) the asteroid's mass, shape, and rotational parameters, (2) the secondary's mass and orbit parameters, (3) the spacecraft mass, surface area, and reflectivity (representing large box-wing-shaped medium-sized spacecraft as well as small satellites), and (4) the time of the mission, and therefore the relative position of the system to the sun. Stable orbital motion (i.e., not requiring thrusting maneuvers) was achieved using the Lagrange points L4/L5 and orbital resonances. This allows for long motion arcs, e.g. of 90 days (L4) and 35 days (resonance) in the Didymos system. The accuracy necessary to deploy a probe into L4, so it can remain there for 35 day, is evaluated by comparisons. Retrograde orbits were found assuring 90 days of low eccentric orbiting for a compact small satellite for a great variety of initial conditions. The comparison of simulations at aphelion and perihelion as well as the different spacecraft show the critical impact of solar radiation pressure on orbital stability. 65,803 Didymos (1996 GT) is shown to be more suitable for orbit phases at the close distances we studied compared to 175,706 (1996 FG3). Two possible obliquities of the Didymos system were considered to study the effects of the inclination on perturbing forces at equinox and solstice, showing that cases of low obliquity or times of equinox are beneficial for spacecraft orbiting.

  17. Near Earth Asteroid (NEA) Scout

    Science.gov (United States)

    Johnson, Les; Castillo-Rogez, Julie; Dervan, Jared; McNutt, Leslie

    2017-01-01

    NASA is developing solar sail propulsion for a near-term Near Earth Asteroid (NEA) reconnaissance mission that will lay the groundwork for the future use of solar sails. The NEA Scout mission will use the sail as primary propulsion allowing it to survey and image one NEA's of interest for future human exploration. NEA Scout will launch on the first mission of the Space Launch System (SLS) in 2018. After its first encounter with the Moon, NEA Scout will enter the sail characterization phase by the 86 square meter sail deployment. A mechanical Active Mass Translation (AMT) system, combined with the remaining ACS propellant, will be used for sail momentum management. The spacecraft will perform a series of lunar flybys to achieve optimum departure trajectory before beginning its two year-long cruise. About one month before the asteroid flyby, NEA Scout will start its approach phase using optical navigation on top of radio tracking. The solar sail will provide NEA Scout continuous low thrust to enable a relatively slow flyby of the target asteroid under lighting conditions favorable to geological imaging. Once complete, NASA will have demonstrated the capability to fly low-cost, high delta V CubeSats to perform interplanetary missions.

  18. Near Earth Asteroid Scout Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In considering targets for human asteroid missions, there are several major factors that will make a significant difference in assessment of mission risks that...

  19. Radar reconnaissance of near-Earth asteroids

    Science.gov (United States)

    Ostro, Steven J.; Giorgini, Jon D.; Benner, Lance A. M.

    2007-05-01

    Radar is a uniquely powerful source of information about near-Earth asteroid (NEA) physical properties and orbits. Measurements of the distribution of echo power in time delay (range) and Doppler frequency (radial velocity) constitute two-dimensional images that can provide spatial resolution finer than a decameter. The best radar images reveal geologic details, including craters and blocks. Radar wavelengths (13 cm at Arecibo, 3.5 cm at Goldstone) are sensitive to the bulk density (a joint function of mineralogy and porosity) and the degree of decimeter-scale structural complexity of the uppermost meter or so of the surface. Radar can determine the masses of binary NEAs via Kepler's third law and of solitary NEAs via measurement of the Yarkovsky acceleration. With adequate orientational coverage, a sequence of images can be used to construct a three-dimensional model, to define the rotation state, to determine the distribution of radar surface properties, and to constrain the internal density distribution. As of mid 2006, radar has detected echoes from 193 NEAs, of which 107 are designated Potentially Hazardous Asteroids. Radar has revealed both stony and metallic objects, principal-axis and non-principal-axis rotators, smooth and extremely rough surfaces, objects that appear to be monolithic fragments and objects likely to be nearly strengthless gravitational aggregates, spheroids and highly elongated shapes, contact-binary shapes, and binary systems. Radar can add centuries to the interval over which close Earth approaches can accurately be predicted, significantly refining collision probability estimates compared to those based on optical astrometry alone. If a small body is on course for a collision with Earth in this century, delay-Doppler radar echoes could almost immediately let us recognize this by distinguishing between an impact trajectory and a near miss, and would dramatically reduce the difficulty and cost of any effort to prevent the collision.

  20. Spectroscopy of near-Earth asteroids

    DEFF Research Database (Denmark)

    Michelsen, René; Nathues, Andreas; Lagerkvist, Claes-Ingvar

    2006-01-01

    We present spectra and taxonomic classifications of 12 Near-Earth Asteroids (NEAs) and 2 inner Main Belt asteroids. The observations were carried out with the ESO 3.5 m NTT and the Danish 1.54 m telescope at La Silla, Chile. Eleven of the investigated NEAs belong to the S class while only one C......-type has been identified. Two NEAs were observed at phase angles larger than 60 degrees introducing significant phase reddening. In order to allow for comparisons between spectra of asteroids observed at different phase angles we make attempts to correct for this effect. However, it turned out...

  1. Spectroscopy of near-Earth asteroids

    DEFF Research Database (Denmark)

    Michelsen, René; Nathues, Andreas; Lagerkvist, Claes-Ingvar

    2006-01-01

    We present spectra and taxonomic classifications of 12 Near-Earth Asteroids (NEAs) and 2 inner Main Belt asteroids. The observations were carried out with the ESO 3.5 m NTT and the Danish 1.54 m telescope at La Silla, Chile. Eleven of the investigated NEAs belong to the S class while only one C......-type has been identified. Two NEAs were observed at phase angles larger than 60 degrees introducing significant phase reddening. In order to allow for comparisons between spectra of asteroids observed at different phase angles we make attempts to correct for this effect. However, it turned out...

  2. Origins for the near-earth asteroids

    Science.gov (United States)

    Binzel, Richard P.; Xu, Shui; Bus, Schelte J.; Bowell, Edward

    1992-01-01

    Because of their short dynamical lifetimes, the population of near-earth asteroids (NEAs) must be resupplied. Two sources have been hypothesized: main-belt asteroids and extinct comet nuclei. A new survey of physical properties for less than 5 kilometers diameter main-belt asteroids reveals that their spin rate and shape distributions are similar to those of NEAs, as is fully consistent with a main-belt origin for most NEAs. Physical data on comet nuclei are limited. If the existing sample is representative of the comet population, analysis of the asteroid and comet samples constrains the fraction of comet nuclei to between 0 and 40 percent of the total NEA population.

  3. EURONEAR - Data Mining of Asteroids and Near Earth Asteroids

    OpenAIRE

    Vaduvescu, O.; Curelaru, L.; Birlan, M.; Bocsa, G.; Serbanescu, L.; Tudorica, A.; Berthier, J.

    2009-01-01

    Besides new observations, mining old photographic plates and CCD image archives represents an opportunity to recover and secure newly discovered asteroids, also to improve the orbits of Near Earth Asteroids (NEAs), Potentially Hazardous Asteroids (PHAs) and Virtual Impactors (VIs). These are the main research aims of the EURONEAR network. As stated by the IAU, the vast collection of image archives stored worldwide is still insufficiently explored, and could be mined for known NEAs and other a...

  4. Spacewatch discovery of near-Earth asteroids

    Science.gov (United States)

    Gehrels, Tom

    1992-01-01

    Our overall scientific goal is to survey the solar system to completion - that is, to find the various populations and to study their statistics, interrelations, and origins. The practical benefit to SERC is that we are finding Earth-approaching asteroids that are accessible for mining. Our system can detect Earth-approachers in the 1-km size range even when they are far away, and can detect smaller objects when they are moving rapidly past Earth. Until Spacewatch, the size range of 6-300 meters in diameter for the near-Earth asteroids was unexplored. This important region represents the transition between the meteorites and the larger observed near-Earth asteroids. One of our Spacewatch discoveries, 1991 VG, may be representative of a new orbital class of object. If it is really a natural object, and not man-made, its orbital parameters are closer to those of the Earth than we have seen before; its delta V is the lowest of all objects known thus far. We may expect new discoveries as we continue our surveying, with fine-tuning of the techniques.

  5. Tracking a Very Near Earth Asteroid

    Science.gov (United States)

    Bruck, R.; Rashid, S.; Peppard, T.

    2013-09-01

    The potential effects of an asteroid passing within close proximity to the Earth were recently realized. During the February 16, 2013 event, Asteroid 2012 DA14 passed within an estimated 27,700 kilometers of the earth, well within the geosynchronous (GEO) orbital belt. This was the closest known approach of a planetoid of this size, in modern history. The GEO belt is a region that is filled with critical communications satellites which provide relays for essential government, business and private datum. On the day of the event, optical instruments at Detachment 3, 21OG, Maui GEODSS were able to open in marginal atmospheric conditions, locate and collect metric and raw video data on the asteroid as it passed a point of near heliocentric orbital propinquity to the Earth. Prior to the event, the Joint Space Operations Center (JSpOC) used propagated trajectory data from NASA's Near Earth Object Program Office at the Jet Propulsion Laboratory to assess potential collisions with man-made objects in Earth orbit. However, the ability to actively track this asteroid through the populated satellite belt not only allowed surveillance for possible late orbital perturbations of the asteroid, but, afforded the ability to monitor possible strikes on all other orbiting bodies of anthropogenic origin either not in orbital catalogs or not recently updated in those catalogs. Although programmed only for tracking satellites in geocentric orbits, GEODSS was able to compensate and maintain track on DA14, collecting one hundred and fifty four metric observations during the event.

  6. Dormant Comets in the Near-Earth Asteroid Population

    NARCIS (Netherlands)

    Mommert, Michael; Harris, Alan W.; Mueller, Michael; Hora, Joseph L.; Trilling, David E.; Knight, Matthew; Bottke, William F.; Thomas, Cristina; Delbo', Marco; Emery, Josh P.; Fazio, Giovanni; Smith, Howard A.

    2015-01-01

    The population of near-Earth objects comprises active comets and asteroids, covering a wide range of dynamical parameters and physical properties. Dormant (or extinct) comets, masquerading as asteroids, have long been suspected of supplementing the near-Earth asteroid (NEA) population. We present a

  7. Capturing near-Earth asteroids around Earth

    Science.gov (United States)

    Hasnain, Zaki; Lamb, Christopher A.; Ross, Shane D.

    2012-12-01

    The list of detected near-Earth asteroids (NEAs) is constantly growing. NEAs are likely targets for resources to support space industrialization, as they may be the least expensive source of certain needed raw materials. The limited supply of precious metals and semiconducting elements on Earth may be supplemented or even replaced by the reserves floating in the form of asteroids around the solar system. Precious metals make up a significant fraction NEAs by mass, and even one metallic asteroid of ˜1km size and fair enrichment in platinum-group metals would contain twice the tonnage of such metals already harvested on Earth. There are ˜1000 NEAs with a diameter of greater than 1 km. Capturing these asteroids around the Earth would expand the mining industry into an entirely new dimension. Having such resources within easy reach in Earth's orbit could provide an off-world environmentally friendly remedy for impending terrestrial shortages, especially given the need for raw materials in developing nations. In this paper, we develop and implement a conceptually simple algorithm to determine trajectory characteristics necessary to move NEAs into capture orbits around the Earth. Altered trajectories of asteroids are calculated using an ephemeris model. Only asteroids of eccentricity less than 0.1 have been studied and the model is restricted to the ecliptic plane for simplicity. We constrain the time of retrieval to be 10 years or less, based on considerations of the time to return on investment. For the heliocentric phase, constant acceleration is assumed. The acceleration required for transporting these asteroids from their undisturbed orbits to the sphere of influence of the Earth is the primary output, along with the impulse or acceleration necessary to effect capture to a bound orbit once the Earth's sphere of influence is reached. The initial guess for the constant acceleration is provided by a new estimation method, similar in spirit to Edelbaum's. Based on the

  8. The Near Earth Asteroid Medical Conditions List

    Science.gov (United States)

    Barr, Yael R.; Watkins, S. D.

    2011-01-01

    Purpose: The Exploration Medical Capability (ExMC) element is one of six elements within NASA s Human Research Program (HRP) and is responsible for addressing the risk of "the inability to adequately recognize or treat an ill or injured crewmember" for exploration-class missions. The Near Earth Asteroid (NEA) Medical Conditions List, constructed by ExMC, is the first step in addressing the above-mentioned risk for the 13-month long NEA mission. The NEA mission is being designed by NASA's Human Space Flight Architecture Team (HAT). The purpose of the conditions list is to serve as an evidence-based foundation for determining which medical conditions could affect a crewmember during the NEA mission, which of those conditions would be of concern and require treatment, and for which conditions a gap in knowledge or technology development exists. This information is used to focus research efforts and technology development to ensure that the appropriate medical capabilities are available for exploration-class missions. Scope and Approach: The NEA Medical Conditions List is part of a broader Space Medicine Exploration Medical Conditions List (SMEMCL), which incorporates various exploration-class design reference missions (DRMs). The conditions list contains 85 medical conditions which could occur during space flight and which are derived from several sources: Long-Term Surveillance of Astronaut Health (LSAH) in-flight occurrence data, The Space Shuttle (STS) Medical Checklist, The International Space Station (ISS) Medical Checklist, and subject matter expert opinion. Each medical condition listed has been assigned a clinical priority and a clinical priority rationale based on incidence, consequence, and mitigation capability. Implementation: The conditions list is a "living document" and as such, new conditions can be added to the list, and the priority of conditions on the list can be adjusted as the DRM changes, and as screening, diagnosis, or treatment capabilities

  9. EURONEAR - Data Mining of Asteroids and Near Earth Asteroids

    CERN Document Server

    Vaduvescu, O; Birlan, M; Bocsa, G; Serbanescu, L; Tudorica, A; Berthier, J

    2009-01-01

    Besides new observations, mining old photographic plates and CCD image archives represents an opportunity to recover and secure newly discovered asteroids, also to improve the orbits of Near Earth Asteroids (NEAs), Potentially Hazardous Asteroids (PHAs) and Virtual Impactors (VIs). These are the main research aims of the EURONEAR network. As stated by the IAU, the vast collection of image archives stored worldwide is still insufficiently explored, and could be mined for known NEAs and other asteroids appearing occasionally in their fields. This data mining could be eased using a server to search and classify findings based on the asteroid class and the discovery date as "precoveries" or "recoveries". We built PRECOVERY, a public facility which uses the Virtual Observatory SkyBoT webservice of IMCCE to search for all known Solar System objects in a given observation. To datamine an entire archive, PRECOVERY requires the observing log in a standard format and outputs a database listing the sorted encounters of ...

  10. The Albedo Distribution of Near Earth Asteroids

    CERN Document Server

    Wright, Edward L; Masiero, Joseph; Grav, Tommy; Bauer, James

    2016-01-01

    The cryogenic WISE mission in 2010 was extremely sensitive to asteroids and not biased against detecting dark objects. The albedos of 428 Near Earth Asteroids (NEAs) observed by WISE during its fully cryogenic mission can be fit quite well by a 3 parameter function that is the sum of two Rayleigh distributions. The Rayleigh distribution is zero for negative values, and follows $f(x) = x \\exp[-x^2/(2\\sigma^2)]/\\sigma^2$ for positive x. The peak value is at x=\\sigma, so the position and width are tied together. The three parameters are the fraction of the objects in the dark population, the position of the dark peak, and the position of the brighter peak. We find that 25.3% of the NEAs observed by WISE are in a very dark population peaking at $p_V = 0.03$, while the other 74.7% of the NEAs seen by WISE are in a moderately dark population peaking at $p_V = 0.168$. A consequence of this bimodal distribution is that the Congressional mandate to find 90% of all NEAs larger than 140 m diameter cannot be satisfied by...

  11. Characterization of the near-Earth Asteroid 2002NY40

    OpenAIRE

    Roberts, Jr., Lewis C.; Hall, Doyle T.; Lambert, John V.; Africano, John L.; Knox, Keith T.; Barros, Jacob K.; Hamada, Kris M.; Liang, Dennis; Sydney, Paul F.; Kervin, Paul

    2007-01-01

    In August 2002, the near-Earth asteroid 2002 NY40, made its closest approach to the Earth. This provided an opportunity to study a near-Earth asteroid with a variety of instruments. Several of the telescopes at the Maui Space Surveillance System were trained at the asteroid and collected adaptive optics images, photometry and spectroscopy. Analysis of the imagery reveals the asteroid is triangular shaped with significant self-shadowing. The photometry reveals a 20-hour period and the spectros...

  12. NASA's Near Earth Asteroid Scout Mission

    Science.gov (United States)

    Johnson, Les; McNutt, Leslie; Castillo-Rogez, Julie

    2017-01-01

    NASA is developing solar sail propulsion for a near-term Near Earth Asteroid (NEA) reconnaissance mission and laying the groundwork for their future use in deep space science and exploration missions. The NEA Scout mission, funded by NASA's Advanced Exploration Systems Program and managed by NASA MSFC, will use the sail as primary propulsion allowing it to survey and image one or more NEA's of interest for possible future human exploration. NEA Scout uses a 6U cubesat (to be provided by NASA's Jet Propulsion Laboratory), an 86 m2 solar sail and will weigh less than 14 kilograms. The solar sail for NEA Scout will be based on the technology developed and flown by the NASA NanoSail-D and The Planetary Society's Lightsail-A. Four 7 m stainless steel booms wrapped on two spools (two overlapping booms per spool) will be motor deployed and pull the sail from its stowed volume. The sail material is an aluminized polyimide approximately 3 microns thick. NEA Scout will launch on the Space Launch System (SLS) first mission in 2018 and deploy from the SLS after the Orion spacecraft is separated from the SLS upper stage. The NEA Scout spacecraft will stabilize its orientation after ejection using an onboard cold-gas thruster system. The same system provides the vehicle Delta-V sufficient for a lunar flyby. After its first encounter with the moon, the 86 m2 sail will deploy, and the sail characterization phase will begin. A mechanical Active Mass Translation (AMT) system, combined with the remaining ACS propellant, will be used for sail momentum management. Once the system is checked out, the spacecraft will perform a series of lunar flybys until it achieves optimum departure trajectory to the target asteroid. The spacecraft will then begin its two year-long cruise. About one month before the asteroid flyby, NEA Scout will pause to search for the target and start its approach phase using a combination of radio tracking and optical navigation. The solar sail will provide

  13. The Nearest of the Near Earth Asteroids

    Science.gov (United States)

    Kortenkamp, Stephen J.

    2014-11-01

    While the orbits of many known near-Earth objects (NEOs) may cross that of Earth, very few NEOs actually approach near to Earth itself. In fact, the majority of NEOs spend most of their orbital periods in the asteroid belt beyond Mars. However, there is a subset of NEOs on orbits which allow for repeated close-encounters with Earth. These objects are locked in a co-orbital resonance with Earth, orbiting the sun in exactly one year. This unusual one-to-one resonance causes the NEOs to appear to be orbiting Earth and gives them their name; quasi-satellites.Despite their close proximity to Earth, only recently have the first quasi-satellites of Earth been detected. These are the asteroids 2003 YN107, 2004 GU9, and 2006 FV35. We carried out N-body computer simulations of these asteroids as well as a larger theoretical population. We demonstrate that quasi-satellite asteroids always remain exceptionally close to Earth, typically just 20-60 times farther than the moon, and undergo two close-encounters with Earth each year. Furthermore, quasi-satellites that eventually escape the resonance can have extremely deep low-velocity close-encounters with Earth as they leave the resonance, some coming well inside the orbit of the moon.When weak drag forces are included in the simulations quasi-satellite objects evolve onto more Earth-like orbits and spiral closer and closer to Earth. This dramatically reduces the relative velocity and distance of closest approach between Earth and the quasi-satellite object. Under the influence of weak drag quasi-satellites objects can develop effective encounter velocities of just a few hundred meters per second, often much less. These low encounter velocities lead to a strong enhancement in Earth’s gravitationally enhanced impact cross-section compared to close-encounters of non-resonant objects with similar initial orbital elements.This research is supported by NASA grant NNX14AN23G.

  14. Near Earth Asteroids:The Celestial Chariots

    CERN Document Server

    Green, Marc; Lacroix, Tom; Marchetto, Jordan; McCaffrey, Erik; Scougal, Erik; Humi, Mayer

    2013-01-01

    In this paper we put forward a proposal to use Near Earth Objects as radiation shield for deep space exploration. In principle these objects can provide also a spacious habitat for the astronauts and their supplies on their journeys. We undertake also a detailed assessment of this proposal for a mission from Earth to Mars.

  15. Compositional differences between meteorites and near-Earth asteroids.

    Science.gov (United States)

    Vernazza, P; Binzel, R P; Thomas, C A; DeMeo, F E; Bus, S J; Rivkin, A S; Tokunaga, A T

    2008-08-14

    Understanding the nature and origin of the asteroid population in Earth's vicinity (near-Earth asteroids, and its subset of potentially hazardous asteroids) is a matter of both scientific interest and practical importance. It is generally expected that the compositions of the asteroids that are most likely to hit Earth should reflect those of the most common meteorites. Here we report that most near-Earth asteroids (including the potentially hazardous subset) have spectral properties quantitatively similar to the class of meteorites known as LL chondrites. The prominent Flora family in the inner part of the asteroid belt shares the same spectral properties, suggesting that it is a dominant source of near-Earth asteroids. The observed similarity of near-Earth asteroids to LL chondrites is, however, surprising, as this meteorite class is relatively rare ( approximately 8 per cent of all meteorite falls). One possible explanation is the role of a size-dependent process, such as the Yarkovsky effect, in transporting material from the main belt.

  16. Physical Properties of Near-Earth Asteroid 2011 MD

    NARCIS (Netherlands)

    Mommert, M.; Farnocchia, D.; Hora, J. L.; Chesley, S. R.; Trilling, D. E.; Chodas, P. W.; Mueller, M.; Harris, A. W.; Smith, H. A.; Fazio, G. G.

    2014-01-01

    We report on observations of near-Earth asteroid 2011 MD with the Spitzer Space Telescope. We have spent 19.9 h of observing time with channel 2 (4.5 {\\mu}m) of the Infrared Array Camera and detected the target within the 2{\\sigma} positional uncertainty ellipse. Using an asteroid thermophysical mod

  17. Physical Properties of Near-Earth Asteroid 2011 MD

    NARCIS (Netherlands)

    Mommert, M.; Farnocchia, D.; Hora, J. L.; Chesley, S. R.; Trilling, D. E.; Chodas, P. W.; Mueller, M.; Harris, A. W.; Smith, H. A.; Fazio, G. G.

    2014-01-01

    We report on observations of near-Earth asteroid 2011 MD with the Spitzer Space Telescope. We have spent 19.9 h of observing time with channel 2 (4.5 {\\mu}m) of the Infrared Array Camera and detected the target within the 2{\\sigma} positional uncertainty ellipse. Using an asteroid thermophysical

  18. Near Earth Asteroids: A Classification System According to Their Shapes

    Science.gov (United States)

    Acevedo, R. D.; Rocca, M.; Rabassa, J.; Ponce, J. F.; Stinco, S.

    2012-09-01

    A new way to classify Near Earth Asteroids (NEAs) according to their shapes is proposed. This classification is based on the asteroid roundness and sphericity in the same way that it is used in geological sciences to describe clasts in mechanical sedimentary rocks.

  19. Lightcurve Analysis of the Near-Earth Asteroid 6063 Jason

    Science.gov (United States)

    Warner, Brian D.; Aznar Macias, Amadeo; Benishek, Vladimir; Oey, Julian; Gross, Roger

    2017-10-01

    CCD photometric observations of the near-Earth asteroid 6063 Jason were made in 2017 June. A collaboration of five observers at widely-separated longitudes proved critical in finding a synodic period of 48.6 h, nearly commensurate with an Earth day, and confirming that the asteroid is most likely tumbling.

  20. From Discovery to Impact - Near Earth Asteroids

    Directory of Open Access Journals (Sweden)

    Miloš Tichý

    2012-10-01

    Full Text Available The Near-Earth Objects (NEOs are the most important of the small bodies of the solar system, having the capability of close approaches to the Earth and the chance to collide with the Earth.  We present here the current system of discovery of these dangerous objects, standards for selecting useful and important targets for NEO follow-up astrometry, system of impact probabilities calculations, and also determination of impact site and evacuation area.

  1. Near Earth Asteroid Characterization for Threat Assessment

    Science.gov (United States)

    Dotson, Jessie; Mathias, Donovan; Wheeler, Lorien; Wooden, Diane; Bryson, Kathryn; Ostrowski, Daniel

    2017-01-01

    Physical characteristics of NEAs are an essential input to modeling behavior during atmospheric entry and to assess the risk of impact but determining these properties requires a non-trivial investment of time and resources. The characteristics relevant to these models include size, density, strength and ablation coefficient. Some of these characteristics cannot be directly measured, but rather must be inferred from related measurements of asteroids and/or meteorites. Furthermore, for the majority of NEAs, only the basic measurements exist so often properties must be inferred from statistics of the population of more completely characterized objects. The Asteroid Threat Assessment Project at NASA Ames Research Center has developed a probabilistic asteroid impact risk (PAIR) model in order to assess the risk of asteroid impact. Our PAIR model and its use to develop probability distributions of impact risk are discussed in other contributions to PDC 2017 (e.g., Mathias et al.). Here we utilize PAIR to investigate which NEA characteristics are important for assessing the impact threat by investigating how changes in these characteristics alter the damage predicted by PAIR. We will also provide an assessment of the current state of knowledge of the NEA characteristics of importance for asteroid threat assessment. The relative importance of different properties as identified using PAIR will be combined with our assessment of the current state of knowledge to identify potential high impact investigations. In addition, we will discuss an ongoing effort to collate the existing measurements of NEA properties of interest to the planetary defense community into a readily accessible database.

  2. Radar observations of near-Earth asteroids from Arecibo Observatory

    Science.gov (United States)

    Rivera-Valentin, Edgard G.; Taylor, Patrick A.; Rodriguez-Ford, Linda A.; Zambrano Marin, Luisa Fernanda; Virkki, Anne; Aponte Hernandez, Betzaida

    2016-10-01

    The Arecibo S-Band (2.38 GHz, 12.6 cm, 1 MW) planetary radar system at the 305-m William E. Gordon Telescope in Arecibo, Puerto Rico is the most active and most sensitive planetary radar facility in the world. Since October 2015, we have detected 56 near-Earth asteroids, of which 17 are classified as potentially hazardous to Earth and 22 are compliant with the Near-Earth Object Human Space Flight Accessible Target Study (NHATS) as possible future robotic- or human-mission destinations. We will present a sampling of the asteroid zoo observed by the Arecibo radar since the 2015 DPS meeting. This includes press-noted asteroids 2015 TB145, the so-called "Great Pumpkin", and 2003 SD220, the so-called "Christmas Eve asteroid".

  3. Variability of Thermal Infrared Emission from Near-Earth Asteroids

    NARCIS (Netherlands)

    Taylor, Patrick A.; Howell, E. S.; Magri, C.; Vervack, R. J.; Nolan, M. C.; Fernandez, Y. R.; Rivkin, A. S.; Mueller, M.

    2009-01-01

    We have measured thermal emission between 2 and 4 microns for several near-Earth asteroids (NEAs) of different taxonomic types with SpeX on the NASA IRTF. Initial results for individual P-, V-, and E-type NEAs were presented at last year's meeting (Howell et al., 2008). Here we present results for t

  4. Density and Macroporosity Distribution of Near Earth Asteroids

    Science.gov (United States)

    Dotson, Jessie L.; Mathias, Donovan

    2017-01-01

    The density of near earth asteroids is a fundamental property which can illuminate the structure of the asteroid, provide clues about it’s collisional history and is key in assessing the hazard of an impact of an NEA with Earth. A low density can be indicative of a rubble pile structure whereas a higher density can imply a monolith and/or a higher metal content. Unfortunately, measuring the density of asteroids is extremely difficult, has only been attempted for a tiny fraction of NEAs and usually results in measurements with large uncertainties. In the absence of density measurements for a specific object, understanding the range and distribution of likely densities can allow for probabilistic assessments of the population and facilitate estimates of the range of reasonable masses for a specific object. We have developed a candidate macroporosity distribution for near earth asteroids based on measurements of meteorite densities and asteroid densities. The macroporosity of an asteroid can be used to aid extrapolation from meteorite physical properties to asteroid physical properties. In addition, we discuss estimating an asteroid density distribution from the macroporosity distribution.

  5. Discovery of a Satellite around a Near-Earth Asteroid

    Science.gov (United States)

    1997-07-01

    Institut fuer Planetenerkundung and Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR) . [2] See ESO Press Release 09/94 of 18 May 1994. [3] Asteroids are small solid planetary bodies revolving around the Sun in orbits that are mostly located in the so-called Main Asteroid Belt, confined between the orbits of Mars and Jupiter. Most of them are thought to be fragments derived from catastrophic, past collisions between larger asteroids. By mid-1997, the orbits of about 8000 asteroids in the solar system were sufficiently well known to allow them to be officially numbered by the rules of the International Astronomical Union. (3671) Dionysus was discovered in 1984 at the Palomar Observatory (California, USA) and is named after the Greek god of wine. [4] The gravitational influence of the giant planet Jupiter can modify the orbits of asteroids located in particular regions of the Main Belt (the effect is refered to as `orbital perturbations'). As a result, the orbit of an asteroid may `cross' that of a major planet, and eventually it may become a NEO , i.e. a near-Earth object. The orbits of NEO's are highly unstable over times comparable to the age of the solar system. This instability can result in a collision with one of the terrestrial (inner) planets, or with the Sun, or in the ejection of the asteroid out of the solar system. The present orbit of (3671) Dionysus is such that this object is not likely to collide with the Earth in the foreseeable future. [5] The method of analyzing the lightcurve of Dionysus consists of `removing' (subtracting) the normal short-period brightness variations due to rotation of the asteroid and plotting the residuals against time, cf. Press Photo 20/97. The residual lightcurve shows a clear resemblance with typical lightcurves of eclipsing binary stellar systems (in which two stars move around each other, producing mutual eclipses) and leads to a model of two bodies revolving around a common gravitational centre, in an orbital

  6. Mining the CFHT Legacy Survey for known Near Earth Asteroids

    CERN Document Server

    Vaduvescu, O; Birlan, M; Toma, R; Badea, M; Dumitru, D; Opriseanu, C; Vidican, D; 10.1002/asna.201011550

    2011-01-01

    The Canada-France-Hawaii Legacy Survey (CFHTLS) comprising about 25 000 MegaCam images was data mined to search for serendipitous encounters of known Near Earth Asteroids (NEAs) and Potentially Hazardous Asteroids (PHAs). A total of 143 asteroids (109 NEAs and 34 PHAs) were found on 508 candidate images which were field corrected and measured carefully, and their astrometry was reported to Minor Planet Centre. Both recoveries and precoveries (apparitions before discovery) were reported, including data for 27 precovered asteroids (20 NEAs and 7 PHAs) and 116 recovered asteroids (89 NEAs and 27 PHAs). Our data prolonged arcs for 41 orbits at first or last opposition, refined 35 orbits by fitting data taken at one new opposition, recovered 6 NEAs at their second opposition and allowed us to ameliorate most orbits and their Minimal Orbital Intersection Distance (MOID), an important parameter to monitor for potential Earth impact hazard in the future.

  7. Spacecraft Conceptual Design for Returning Entire Near-Earth Asteroids

    Science.gov (United States)

    Brophy, John R.; Oleson, Steve

    2012-01-01

    In situ resource utilization (ISRU) in general, and asteroid mining in particular are ideas that have been around for a long time, and for good reason. It is clear that ultimately human exploration beyond low-Earth orbit will have to utilize the material resources available in space. Historically, the lack of sufficiently capable in-space transportation has been one of the key impediments to the harvesting of near-Earth asteroid resources. With the advent of high-power (or order 40 kW) solar electric propulsion systems, that impediment is being removed. High-power solar electric propulsion (SEP) would be enabling for the exploitation of asteroid resources. The design of a 40-kW end-of-life SEP system is presented that could rendezvous with, capture, and subsequently transport a 1,000-metric-ton near-Earth asteroid back to cislunar space. The conceptual spacecraft design was developed by the Collaborative Modeling for Parametric Assessment of Space Systems (COMPASS) team at the Glenn Research Center in collaboration with the Keck Institute for Space Studies (KISS) team assembled to investigate the feasibility of an asteroid retrieval mission. Returning such an object to cislunar space would enable astronaut crews to inspect, sample, dissect, and ultimately determine how to extract the desired materials from the asteroid. This process could jump-start the entire ISRU industry.

  8. The EURONEAR Lightcurve Survey of Near Earth Asteroids

    Science.gov (United States)

    Vaduvescu, O.; Aznar Macias, A.; Tudor, V.; Predatu, M.; Galád, A.; Gajdoš, Š.; Világi, J.; Stevance, H. F.; Errmann, R.; Unda-Sanzana, E.; Char, F.; Peixinho, N.; Popescu, M.; Sonka, A.; Cornea, R.; Suciu, O.; Toma, R.; Santos-Sanz, P.; Sota, A.; Licandro, J.; Serra-Ricart, M.; Morate, D.; Mocnik, T.; Diaz Alfaro, M.; Lopez-Martinez, F.; McCormac, J.; Humphries, N.

    2017-07-01

    This data paper presents lightcurves of 101 near Earth asteroids (NEAs) observed mostly between 2014 and 2017 as part of the EURONEAR photometric survey using 11 telescopes with diameters between 0.4 and 4.2 m located in Spain, Chile, Slovakia and Romania. Most targets had no published data at the time of observing, but some objects were observed in the same period mainly by B. Warner, allowing us to confirm or improve the existing results. To plan the runs and select the targets, we developed the public Long Planning tool in PHP. For preliminary data reduction and rapid follow-up planning we developed the LiDAS pipeline in Python and IRAF. For final data reduction, flux calibration, night linkage and Fourier fitting, we used mainly MPO Canopus. Periods of 18 targets are presented for the first time, and we could solve or constrain rotation for 16 of them. We secured periods for 45 targets (U˜ 3 ), found candidate periods for other 16 targets (U˜ 2 ), and we propose tentative periods for other 32 targets (U˜ 1 ). We observed 7 known or candidate binary NEAs, fiting 3 of them (2102 Tantalus, 5143 Heracles and 68348). We observed 8 known or candidate tumbling NEAs, deriving primary periods for 3 objects (9400, 242708 and 470510). We evidenced rapid oscillations (few minutes) and could fit fast tentative periods TP2 for 5 large newly suggested tumbling or binary candidates (27346, 112985, 285625, 377732, 408980), probably discovering at least one new binary NEA (2011 WO41). We resolved periods of 4 special objects which include two proposed space mission targets (163249 and 101955 Bennu), one very fast rotator NEA discovered by EURONEAR (2014 NL52) and the "Halloween asteroid" (2015 TB145). Using Mercator in simultaneous 3 band MAIA imaging, we could evidence for the first time clear variation in the color lightcurves of 10 NEAs. The periods derived from the g-r color lightcurves are found to match individual band period fits for 4 NEAs (27346, 86067, 112985 and

  9. The EURONEAR Lightcurve Survey of Near Earth Asteroids

    Science.gov (United States)

    Vaduvescu, O.; Macias, A. Aznar; Tudor, V.; Predatu, M.; Galád, A.; Gajdoš, Š.; Világi, J.; Stevance, H. F.; Errmann, R.; Unda-Sanzana, E.; Char, F.; Peixinho, N.; Popescu, M.; Sonka, A.; Cornea, R.; Suciu, O.; Toma, R.; Santos-Sanz, P.; Sota, A.; Licandro, J.; Serra-Ricart, M.; Morate, D.; Mocnik, T.; Alfaro, M. Diaz; Lopez-Martinez, F.; McCormac, J.; Humphries, N.

    2017-08-01

    This data paper presents lightcurves of 101 near Earth asteroids (NEAs) observed mostly between 2014 and 2017 as part of the EURONEAR photometric survey using 11 telescopes with diameters between 0.4 and 4.2 m located in Spain, Chile, Slovakia and Romania. Most targets had no published data at the time of observing, but some objects were observed in the same period mainly by B. Warner, allowing us to confirm or improve the existing results. To plan the runs and select the targets, we developed the public Long Planning tool in PHP. For preliminary data reduction and rapid follow-up planning we developed the LiDAS pipeline in Python and IRAF. For final data reduction, flux calibration, night linkage and Fourier fitting, we used mainly MPO Canopus. Periods of 18 targets are presented for the first time, and we could solve or constrain rotation for 16 of them. We secured periods for 45 targets (U˜ 3), found candidate periods for other 16 targets (U˜ 2), and we propose tentative periods for other 32 targets (U˜ 1). We observed 7 known or candidate binary NEAs, fiting 3 of them (2102 Tantalus, 5143 Heracles and 68348). We observed 8 known or candidate tumbling NEAs, deriving primary periods for 3 objects (9400, 242708 and 470510). We evidenced rapid oscillations (few minutes) and could fit fast tentative periods TP2 for 5 large newly suggested tumbling or binary candidates (27346, 112985, 285625, 377732, 408980), probably discovering at least one new binary NEA (2011 WO41). We resolved periods of 4 special objects which include two proposed space mission targets (163249 and 101955 Bennu), one very fast rotator NEA discovered by EURONEAR (2014 NL52) and the "Halloween asteroid" (2015 TB145). Using Mercator in simultaneous 3 band MAIA imaging, we could evidence for the first time clear variation in the color lightcurves of 10 NEAs. The periods derived from the g- r color lightcurves are found to match individual band period fits for 4 NEAs (27346, 86067, 112985 and

  10. Are There Meteors Originated from Near Earth Asteroid (25143) Itokawa?

    CERN Document Server

    Ohtsuka, K; Abe, M; Yano, H; Watanabe, J

    2008-01-01

    As a result of a survey of Itokawid meteors (i.e., meteors originated from Near Earth Asteroid (25143) Itokawa = 1998SF36), from among the multi-station optical meteor orbit data of ~15000 orbits, and applying the D-criteria, we could find five Itokawid meteor candidates. We also analyzed corresponding mineral materials of the Itokawid candidates through their trajectory and atmospheric data. We conclude, on the basis of our investigation, that the fireball, MORP172, is the strongest Itokawid candidate.

  11. Near Earth Asteroid redirect missions based on gravity assist maneuver

    Science.gov (United States)

    Ledkov, Anton; Shustov, Boris M.; Eismont, Natan; Boyarsky, Michael; Nazirov, Ravil; Fedyaev, Konstantin

    During last years several events attracted world community attention to the hazards of hitting the Earth by sky objects. One of these objects is Apophis asteroid what was expected with nonzero probability to hit the Earth in 2036. Luckily after more precise measurements this event is considered as practically improbable. But the other object has really reached the Earth, entered the atmosphere in the Chelyabinsk area and caused vast damages. After this the hazardous near Earth objects problem received practical confirmation of the necessity to find the methods of its resolution. The methods to prevent collision of the dangerous sky object with the Earth proposed up to now look not practical enough if one mentions such as gravitational tractor or changing the reflectivity of the asteroid surface. Even the method supposing the targeting of the spacecraft to the hazardous object in order to deflect it from initial trajectory by impact does not work because its low mass as compared with the mass of asteroid to be deflected. For example the mass of the Apophis is estimated to be about 40 million tons but the spacecraft which can be launched to intercept the asteroid using contemporary launchers has the mass not more than 5 tons. So the question arises where to find the heavier projectile which is possible to direct to the dangerous object? The answer proposed in our paper is very simple: to search it among small near Earth asteroids. As small ones we suppose those which have the cross section size not more than 12-15 meters and mass not exceeding 1500 -1700 tons. According to contemporary estimates the number of such asteroids is not less than 100000. The other question is how to redirect such asteroid to the dangerous one. In the paper the possibilities are studied to use for that purpose gravity assist maneuvers near Earth. It is shown that even among asteroids included in contemporary catalogue there are the ones which could be directed to the trajectory of the

  12. Near Earth Asteroid Scout Thrust and Torque Model

    Science.gov (United States)

    Heaton, Andrew; Ahmad, Naeem; Miller, Kyle

    2017-01-01

    The Near Earth Asteroid (NEA) Scout is a solar sail mission whose objective is to scout at least one Near Earth Asteroid in preparation for manned missions to asteroids. NEA Scout will use a solar sail as the primary means of propulsion. Thus it is important for mission planning to accurately characterize the thrust of the sail. Additionally, the solar sail creates a relatively large solar disturbance torque that must be mitigated. For early mission design studies a flat plate model of the solar sail with a fixed center of pressure was adequate, but as mission concepts and the sail design matured, greater fidelity was required. Here we discuss the progress to a three-dimensional sail model that includes the effects of tension and thermal deformation that has been derived from a large structural Finite Element Model (FEM) developed by the Langley Research Center. We have found that the deformed sail membrane affects torque relatively much more than thrust. We have also found that other than uncertainty over the precise shape, the effect of small (approximately millimeter scale) wrinkles on the diffusivity of the sail is the leading remaining source of uncertainty. We demonstrate that millimeter-scale wrinkles can be modeled analytically as a change in the fraction of specular reflection. Finally we discuss the implications of these results for the NEA Scout mission.

  13. Volatile Survival on Near-Earth Asteroid 2008 EV5

    Science.gov (United States)

    Pohl, Leos; Britt, Daniel

    2016-10-01

    with the model of near Earth asteroids to determine the possible scenarios of dehydration of 2008 EV5.

  14. Designing Medical Support for a Near-Earth Asteroid Mission

    Science.gov (United States)

    Watkins, S. D.; Charles, J. B.; Kundrot, C. E.; Barr, Y. R.; Barsten, K. N.; Chin, D. A.; Kerstman, E. L.; Otto, C.

    2011-01-01

    This panel will discuss the design of medical support for a mission to a near-Earth asteroid (NEA) from a variety of perspectives. The panelists will discuss the proposed parameters for a NEA mission, the NEA medical condition list, recommendations from the NASA telemedicine workshop, an overview of the Exploration Medical System Demonstration planned for the International Space Station, use of predictive models for mission planning, and mission-related concerns for behavioral health and performance. This panel is intended to make the audience aware of the multitude of factors influencing medical support during a NEA mission.

  15. LSST's Projected Near-Earth Asteroid Discovery Performance

    Science.gov (United States)

    Chesley, Steven R.; Veres, Peter

    2016-10-01

    The Large Synoptic Survey Telescope (LSST) is an ambitious project that has the potential to make major advances in Near-Earth Asteroid search efforts. With construction already underway and major optical elements complete, first light is set for 2020, followed by two years of commissioning. Once regular survey operations begin in 2022, LSST will systematically survey the observable sky over a ten-year period from its site on Cerro Pachon, Chile. With an 8.4 m aperture (6.5 m effective), 9.6 square degree field of view, and a 3.2-Gigapixel camera, LSST represents the most capable asteroid survey instrument ever built. LSST will be able cover over 6000 square degrees of sky per clear night with single visit exposures of 30 s, reaching a faint limit of 24.5 mag in the r band. However the cadence of survey operations is a critical factor for the near-Earth asteroid search performance, and there are multiple science drivers with different cadence objectives that are competing to shape the final survey strategy. We examine the NEA search performance of various LSST search strategies, paying particular attention to the challenges of linking large numbers asteroid detections in the presence of noise. Our approach is to derive lists of synthetic detections for a given instantiation of the LSST survey, based on an assumed model for the populations of solar system objects from the main asteroid belt inwards to the near-Earth population. These detection lists are combined with false detection lists that model both random noise and non-random artifacts resulting from image differencing algorithms. These large detection lists are fed to the Moving Object Processing System (MOPS), which attempts to link the synthetic detections correctly without becoming confused or overwhelmed by the false detections. The LSST baseline survey cadence relies primarily on single night pairs of detections, with roughly 30-60 min separating elements of the pair. The strategy of using pairs is an

  16. Lightcurves for Two Near-Earth Asteroids by Asteroids Observers (OBAS) - MPPD: 2016 April-May

    Science.gov (United States)

    Martinez, Vicente Mas; Silva, Gonzalo Fornas; Martinez, Angel Flores; Garceran, Alfonso Carreno; Mansego, Enrique Arce; Rodriguez, Pedro Brines; de Haro, Juan Lozano; Silva, Alvaro Fornas; Chiner, Onofre Rodrigo; Porta, David Herrero

    2016-10-01

    We report on the results of photometric analysis of two near-Earth asteroids (NEA) by Asteroids Observers (OBAS). This work is part of the Minor Planet Photometric Database (MPPD) project initiated by a group of Spanish amateur astronomers. We have managed to obtain a number of accurate and complete lightcurves as well as some additional incomplete lightcurves to help analysis at future oppositions.

  17. Near Earth Asteroid Solar Sail Engineering Development Unit Test Program

    Science.gov (United States)

    Lockett, Tiffany Russell; Few, Alexander; Wilson, Richard

    2017-01-01

    The Near Earth Asteroid (NEA) Scout project is a 30x20x10cm (6U) cubesat reconnaissance mission to investigate a near Earth asteroid utilizing an 86m2 solar sail as the primary propulsion system. This will be the largest solar sail NASA will launch to date. NEA Scout is a secondary payload currently manifested on the maiden voyage of the Space Launch System in 2018. In development of the solar sail subsystem, design challenges were identified and investigated for packaging within a 6U form factor and deployment in cis-lunar space. Analysis furthered understanding of thermal, stress, and dynamics of the stowed system and matured an integrated sail membrane model for deployed flight dynamics. This paper will address design, fabrication, and lessons learned from the NEA Scout solar sail subsystem engineering development unit. From optical properties of the sail material to folding and spooling the single 86m2 sail, the team has developed a robust deployment system for the solar sail. This paper will also address expected and received test results from ascent vent, random vibration, and deployment tests.

  18. Do Planetary Encounters Reset Surfaces of Near Earth Asteroids?

    CERN Document Server

    Nesvorny, David; Vokrouhlicky, David; Chapman, Clark R; Rafkin, Scot

    2010-01-01

    Processes such as the solar wind sputtering and micrometeorite impacts can modify optical properties of surfaces of airless bodies. This explains why spectra of the main belt asteroids, exposed to these `space weathering' processes over eons, do not match the laboratory spectra of ordinary chondrite (OC) meteorites. In contrast, an important fraction of Near Earth Asteroids (NEAs), defined as Q-types in the asteroid taxonomy, display spectral attributes that are a good match to OCs. Here we study the possibility that the Q-type NEAs underwent recent encounters with the terrestrial planets and that the tidal gravity (or other effects) during these encounters exposed fresh OC material on the surface (thus giving it the Q-type spectral properties). We used numerical integrations to determine the statistics of encounters of NEAs to planets. The results were used to calculate the fraction and orbital distribution of Q-type asteroids expected in the model as a function of the space weathering timescale, t_sw (see m...

  19. Near Earth Asteroid Scout Solar Sail Thrust and Torque Model

    Science.gov (United States)

    Heaton, Andy; Ahmad, Naeem; Miller, Kyle

    2017-01-01

    The Near Earth Asteroid (NEA) Scout is a solar sail mission whose objective is to scout at least one Near Earth Asteroid to help prepare for human missions to Near Earth Asteroids. NEA Scout will launch as a secondary payload on the first SLS-Orion mission. NEA Scout will perform a small trim maneuver shortly after deploy from the spent SLS upper stage using a cold gas propulsion system, but from that point on will depend entirely on the solar sail for thrust. As such, it is important to accurately characterize the thrust of the sail in order to achieve mission success. Additionally, the solar sail creates a relatively large solar disturbance torque that must be mitigated. For early mission design studies a flat plate model of the solar sail with a fixed center of pressure was adequate, but as mission concepts and the sail design matured, greater fidelity was required. Here we discuss the progress to a three-dimensional sail model that includes the effects of tension and thermal deformation that has been derived from a large structural Finite Element Model (FEM) developed by the Langley Research Center. We have found that the deformed sail membrane affects torque relatively much more than thrust; a flat plate model could potentially model thrust well enough to close mission design studies, but a three-dimensional solar sail is essential to control system design. The three-dimensional solar sail model revealed that thermal deformations of unshielded booms would create unacceptably large solar disturbance torques. The original large FEM model was used in control and mission simulations, but was resulted in simulations with prohibitive run times. This led us to adapt the Generalized Sail Model (GSM) of Rios-Reyes. A design reference sail model has been baselined for NEA Scout and has been used to design the mission and control system for the sailcraft. Additionally, since NEA Scout uses reaction wheels for attitude pointing and control, the solar torque model is

  20. A Potpourri of Near-Earth Asteroid Observations

    Science.gov (United States)

    Tholen, David J.; Ramanjooloo, Yudish; Fohring, Dora; Hung, Denise; Micheli, Marco

    2016-10-01

    Ongoing astrometric follow-up of near-Earth asteroids has yielded a variety of interesting results. In the limited space of a DPS abstract, three recently observed objects are worth mentioning.2008 HU4 is among the most accessible asteroids for a human space flight mission. We successfully recovered this object at a second opposition on 2016 April 26 despite the large ephemeris uncertainty. The small size of this asteroid makes it relatively easy to detect the departure from purely gravitational motion caused by solar radiation pressure, which can be used to estimate the density of the object. At the time of this writing, the object remains bright enough for additional observations, so we expect to improve on our five-sigma detection of a relatively low density (roughly similar to water, indicating a high porosity) between now and the DPS meeting.2016 HO3 is a newly-discovered co-orbital with the Earth. Our 2016 May 10-11 observations extended the observational arc by enough to permit backward extrapolation that led to prediscovery observations by Pan-STARRS in 2015, and then annually back to 2011, and ultimately to Sloan DSS observations in 2004. The 12-year arc is sufficient to examine the dynamical behavior of the object, which shows how it will remain in the vicinity of the Earth for decades, if not centuries. Our observations also revealed a rapid rotation (less than a half hour) with large brightness variation (in excess of 1 magnitude), which helps to explain why this object eluded discovery until this year.2011 YV62 is among the top 20 largest near-Earth asteroids with Earth impact solutions (in 2078 and 2080). At the time of this writing, the object is flagged as being "lost", but a re-examination of observations made in 2013 and 2015 finally yielded a successful recovery at a magnitude fainter than 24. We expect the new observations to eliminate the impact possibilities. The story behind this difficult recovery is fascinating.

  1. The Obliquity Distribution of Near-Earth Asteroids

    Science.gov (United States)

    Chesley, Steven R.; Farnocchia, D.; Cotto-Figueroa, D.; Statler, T. S.

    2013-05-01

    Abstract (2,250 Maximum Characters): Direct estimates of the Yarkovsky effect on near-Earth asteroids (NEAs) indicate that detectable semimajor axis drift rates are approximately 2-4 times more likely to be negative than positive (Nugent et al., AJ 144, 2012; Farnocchia et al., Icarus in press, 2013). The Yarkovsky effect induces a semimajor axis drift rate that is proportional to the cosine of the obliquity, and thus the excess of negative drift rates suggests an excess of retrograde rotation among the NEAs. This reinforces an earlier result from light curve inversion techniques (La Spina et al., Nature 428, 2004). The retrograde excess is presumed to arise from the nu6 resonance, which is situated near the inner edge of the main belt. Main-belt asteroids that are Yarkovsky-driven into the near-Earth region via the nu6 resonance must have a negative semimajor axis drift and therefore retrograde rotation, leading to an overabundance of retrograde rotators, even though other source regions may have parity between retrograde and direct rotators. The Yarkovsky detections do not directly shed light on the relative presence of mid-range obliquities, which tend to have low drift rates and therefore fail to yield statistically significant drift estimates, but they do present significantly different selection effects when compared to light curve inversions. We present preliminary results from our effort to derive independent constraints on the obliquity distribution of NEAs based on the distribution of estimated semimajor axis drift rates among the NEA population and their associated uncertainties. Our approach to solving the inverse problem starts by deriving the drift rates and associated signal-to-noise ratios for a semi-synthetic NEA population that assumes a parameterized obliquity distribution. The parameters are adjusted until the simulated distributions match the observed distributions, yielding not only an estimated distribution, but also uncertainties and

  2. Rendezvous missions to temporarily captured near Earth asteroids

    Science.gov (United States)

    Brelsford, S.; Chyba, M.; Haberkorn, T.; Patterson, G.

    2016-04-01

    Missions to rendezvous with or capture an asteroid present significant interest both from a geophysical and safety point of view. They are key to the understanding of our solar system and are stepping stones for interplanetary human flight. In this paper, we focus on a rendezvous mission with 2006 RH120, an asteroid classified as a Temporarily Captured Orbiter (TCO). TCOs form a new population of near Earth objects presenting many advantages toward that goal. Prior to the mission, we consider the spacecraft hibernating on a Halo orbit around the Earth-Moon's L2 libration point. The objective is to design a transfer for the spacecraft from the parking orbit to rendezvous with 2006 RH120 while minimizing the fuel consumption. Our transfers use indirect methods, based on the Pontryagin Maximum Principle, combined with continuation techniques and a direct method to address the sensitivity of the initialization. We demonstrate that a rendezvous mission with 2006 RH120 can be accomplished with low delta-v. This exploratory work can be seen as a first step to identify good candidates for a rendezvous on a given TCO trajectory.

  3. Near-Earth asteroids orbit propagation with Gaia observations

    CERN Document Server

    Bancelin, D; Thuillot, W

    2016-01-01

    Gaia is an astrometric mission that will be launched in 2013 and set on L2 point of Lagrange. It will observe a large number of Solar System Objets (SSO) down to magnitude 20. The Solar System Science goal is to map thousand of Main Belt asteroids (MBAs), Near Earth Objects (NEOs) (including comets) and also planetary satellites with the principal purpuse of orbital determination (better than 5 mas astrometric precision), determination of asteroid mass, spin properties and taxonomy. Besides, Gaia will be able to discover a few objects, in particular NEOs in the region down to the solar elongation 45{\\deg} which are harder to detect with current ground-based surveys. But Gaia is not a follow-up mission and newly discovered objects can be lost if no ground-based recovery is processed. The purpose of this study is to quantify the impact of Gaia data for the known NEAs population and to show how to handle the problem of these discoveries when faint number of observations and thus very short arc is provided.

  4. Seven Near-Earth Asteroids at Asteroids Observers (OBAS) - MPPD: 2016 June-November

    Science.gov (United States)

    Lozano, Juan; Flores, Angel; Mas, Vicente; Fornas, Gonzalo; Rodrigo, Onofre; Brines, Pedro; Forna, Alvaro; Herrero, David; Carreño, Alfonso; Arce, Enrique

    2017-04-01

    We report on the results of photometric analysis on seven near-Earth asteroids (NEA) by Asteroides Observers (OBAS). This work is part of the Minor Planet Photometric Database effort that was initiated by a group of Spanish amateur astronomers. We have managed to obtain a number of accurate and complete lightcurves as well as some additional incomplete lightcurves to help analysis at future oppositions.

  5. Spectral Classification of NEOWISE Observed Near-Earth Asteroids

    Science.gov (United States)

    Desira, Christopher

    2017-01-01

    Near-Earth asteroids (NEAs) allow us to determine the properties of the smallest solar system bodies in the sub-kilometer size range. Large (>few km) NEAs have albedos which span a wide range from ~0.05 to ~0.3 and are known to correlate with asteroid composition, determined by analysing the shape of their optical reflectance spectra. It is, however, still unknown how this relationship extends into the sub-kilometer population.NEOWISE has performed a thermal infrared survey that provides the largest inventory to date of well-determined sizes and albedos for NEAs, including many in the sub-km population. This provides an opportunity to test the albedo-surface composition correlation in a new size regime. If it is found to hold, then a simple optical spectrum can give a well-constrained albedo and size estimate without the need for thermal IR measurements.The sizes and composition of many more sub-km sized NEAs are needed to aid in the understanding of the formation/evolution of the inner solar system and the characterisation of potentially hazardous objects, possible mission targets and even commercial mining operations.We obtained optical spectra of sub-kilometer NEOWISE-observed NEAs using the 1.5m Tillinghast telescope and the FAST spectrograph at the Whipple Observatory on Mt Hopkins, Arizona. We performed a taxonomic classification to identify their likely composition and combined this with NEOWISE data to look for known correlations between main belt asteroid spectral types and their optical albedos. Additionally, we tested the robustness of current data reduction methods in order to increase our confidence in the spectral classifications of NEAs.

  6. Radar Interferometric Imaging of Near-Earth Asteroids

    Science.gov (United States)

    Margot, J. L.; Nolan, M. C.

    1999-09-01

    High resolution imagery and a three-dimensional characterization of Near-Earth Asteroids (NEAs) can be obtained with ground-based radars. The Arecibo and Goldstone radar systems yield data at spatial resolutions comparable to the highest resolution spacecraft images of asteroids obtained to date. The use of radar interferometry techniques can further improve imaging and shape reconstruction algorithms [1],[2] and may allow direct measurements of the topography of NEAs. A two-element radar interferometer of appropriate baseline provides an observable, the interferometric phase, which can be used to extract three-dimensional information about the target [3], hence giving additional control in shape modeling procedures. The measurement of interferometric phase also opens the possibility of mapping the topography of an asteroid, in a manner similar to that applied recently to the Moon [4]. Simulations show that this is feasible when potential ambiguities in range-Doppler imaging are avoided, for instance when elongated objects are in a favorable orientation. Radar interferometric imaging of 6489 Golevka was attempted during its June 1999 close approach to Earth [5]. The Arecibo 305 m telescope was used to transmit, and the DSN 70 m antenna in Madrid formed the second element of the interferometer. The Arecibo-Madrid baseline defined an ideal fringe pattern for interferometric mapping, but technical difficulties prevented imaging of the Madrid data. Radar interferometry concepts and simulation results will be presented, as well as any new data acquired before the meeting. [1] R. S. Hudson and S. J. Ostro (1994). Science, 263, 940. [2] R. S. Hudson and S. J. Ostro (1995). Science, 270, 84. [3] I. I. Shapiro et al. (1972). Science, 178, 939. [4] J. L. Margot et al. (1999). Science, 284, 1658. [5] J. L. Margot and M. C. Nolan (1999). ACM Meeting, July 26-30, Cornell University, Ithaca, NY.

  7. Steve Ostro and the Near-Earth Asteroid Impact Hazard

    Science.gov (United States)

    Chapman, Clark R.

    2009-09-01

    The late Steve Ostro, whose scientific interests in Near-Earth Asteroids (NEAs) primarily related to his planetary radar research in the 1980s, soon became an expert on the impact hazard. He quickly realized that radar provided perspectives on close-approaching NEAs that were both very precise as well as complementary to traditional astrometry, enabling good predictions of future orbits and collision probabilities extending for centuries into the future. He also was among the few astronomers who considered the profound issues raised by this newly recognized hazard and by early suggestions of how to mitigate the hazard. With Carl Sagan, Ostro articulated the "deflection dilemma" and other potential low-probability but real dangers of mitigation technologies that might be more serious than the low-probability impact hazard itself. Yet Ostro maintained a deep interest in developing responsible mitigation technologies, in educating the public about the nature of the impact hazard, and in learning more about the population of threatening bodies, especially using the revealing techniques of delay-doppler radar mapping of NEAs and their satellites.

  8. Near-Earth Asteroid Characterisation: Gotta catch 'em All!

    Science.gov (United States)

    Zegmott, Tarik Joseph; Galache, Jose Luis; Elvis, Martin

    2015-01-01

    Near-Earth Asteroids (NEAs) are a subject of interest for several reasons: They pose a hazard to Earth through collisions, are prime targets for human exploration missions, and can contain valuable materials such water or Platinum Group Metals (PGMs). Since the 2005 George E. Brown Congressional mandate to find 90% of NEAs >140 m by 2020, the number of NEAs detected has increased to over 1000/year. However the rate of NEA characterisation has not kept pace and is currently only ~10% of the discovery rate. An earlier study (Galache et al. 2014) has shown that most NEAs are found near their brightest and fade below follow-up magnitudes within ~10 days. Moreover small (H>22) NEAs are typically much fainter on any subsequent apparition within 10 years. Hence there is a strong 'need for speed' in making follow-up measurements. We have studied how many NEAs can be characterised per year based on telescope size, location or type, using available ephemeris data from the Minor Planet Centre. We describe how these constraints define strategies for characterising NEAs in bulk.

  9. Near Earth Asteroids- Prospection, Orbit Modification and Mining

    Science.gov (United States)

    Grandl, W.; Bazso, A.

    2014-04-01

    The number of known Near Earth Asteroids (NEAs) has increased continuously during the last decades. Now we understand the role of asteroid impacts for the evolution of life on Earth. To ensure that mankind will survive in the long run, we have to face the "asteroid threat" seriously. On one hand we will have to develop methods of detection and deflection for Hazardous Asteroids, on the other hand we can use these methods to modify their orbits and exploit their resources. Rare-earth elements, rare metals like platinum group elements, etc. may be extracted more easily from NEAs than from terrestrial soil, without environmental pollution or political and social problems. In a first step NEAs, which are expected to contain resources like nickel-iron, platinum group metals or rare-earth elements, will be prospected by robotic probes. Then a number of asteroids with a minimum bulk density of 2 g/cm^3 and a diameter of 150 to 500 m will be selected for mining. Given the long duration of an individual mission time of 10-20 years, the authors propose a "pipeline" concept. While the observation of NEAs can be done in parallel, the precursor missions of the the next phase can be launched in short intervals, giving time for technical corrections and upgrades. In this way a continuous data flow is established and there are no idle times. For our purpose Potentially Hazardous Asteroids (PHAs) seem to be a favorable choice for the following reasons: They have frequent closeencounters to Earth, their minimum orbit intersection distance is less than 0.05 AU (Astronomic Units) and they have diameters exceeding 150 meters. The necessary velocity change (delta V) for a spaceship is below 12 km/s to reach the PHA. The authors propose to modify the orbits of the chosen PHAs by orbital maneuvers from solar orbits to stable Earth orbits beyond the Moon. To change the orbits of these celestial bodies it is necessary to develop advanced propulsion systems. They must be able to deliver high

  10. Near-Earth Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2015 June-September

    Science.gov (United States)

    Warner, Brian D.

    2016-01-01

    Lightcurves for 46 near-Earth asteroids (NEAs) were obtained at the Center for Solar System Studies-Palmer Divide Station (CS3-PDS) from 2015 June-September. Four of the asteroids showed indications of non-principal axis rotation (NPAR), or tumbling, (9400) 1994 TW1, (86666) 2000 FL10, (154807) 2004 PP97, and (206378) 2003 RB, but there were insufficient data for full analysis. On the other hand, 2015 JY1 is a confirmed tumbler with a dominate period of 6.442 h and a likely second period of 11.42 h. Evidence of the satellite for the known binary system (385186) 1994 AW1 was found. The estimated size ratio of Ds/Dp >= 0.25 is in good agreement with earlier results. A third period was also found but its origin is not confirmed.

  11. Near-Earth asteroid satellite spins under spin-orbit coupling

    Energy Technology Data Exchange (ETDEWEB)

    Naidu, Shantanu P.; Margot, Jean-Luc [Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, CA 90095 (United States)

    2015-02-01

    We develop a fourth-order numerical integrator to simulate the coupled spin and orbital motions of two rigid bodies having arbitrary mass distributions under the influence of their mutual gravitational potential. We simulate the dynamics of components in well-characterized binary and triple near-Earth asteroid systems and use surface of section plots to map the possible spin configurations of the satellites. For asynchronous satellites, the analysis reveals large regions of phase space where the spin state of the satellite is chaotic. For synchronous satellites, we show that libration amplitudes can reach detectable values even for moderately elongated shapes. The presence of chaotic regions in the phase space has important consequences for the evolution of binary asteroids. It may substantially increase spin synchronization timescales, explain the observed fraction of asychronous binaries, delay BYORP-type evolution, and extend the lifetime of binaries. The variations in spin rate due to large librations also affect the analysis and interpretation of light curve and radar observations.

  12. Near-Earth Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2016 April-July

    Science.gov (United States)

    Warner, Brian D.

    2016-10-01

    Lightcurves for 31 near-Earth asteroids (NEAs), obtained at the Center for Solar System Studies-Palmer Divide Station (CS3-PDS) from 2016 April-July, were analyzed for rotation period and signs of satellites or tumbling.

  13. Near-Earth Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2016 October-December

    Science.gov (United States)

    Warner, Brian D.

    2017-04-01

    Lightcurves for 33 near-Earth asteroids (NEAs) obtained at the Center for Solar System Studies-Palmer Divide Station (CS3-PDS) from 2016 October through December were analyzed for rotation period and signs of satellites or tumbling.

  14. Around 1500 near-Earth-asteroid orbits improved via EURONEAR

    Science.gov (United States)

    Vaduvescu, O.; Hudin, L.; Birlan, M.; Popescu, M.; Tudorica, A.; Toma, R.

    2014-07-01

    Born in 2006 in Paris, the European Near Earth Asteroids Research project (EURONEAR, euronear.imcce.fr) aims ''to study NEAs and PHAs using existing telescopes available to its network and hopefully in the future some automated dedicated 1--2 m facilities''. Although we believe the first aim is fulfilled, the second was not achieved yet, requiring serious commitment from the European NEA researchers and funding agencies. Mainly using free labor by about 30 students and amateur astronomers (from Romania, Chile, UK, France, etc), the PI backed up by his associates M. Birlan (IMCCE Paris) and J. Licandro (IAC Tenerife) and a few other astronomers of the EURONEAR network having access to a few telescopes are approaching around 1,500 observed NEAs whose orbits were improved based on our astrometric contributions. To achive this milestone, we used two main resources and a total of 15 facilities: i) Observing time obtained at 11 professional 1--4 m class telescopes (Chile, La Palma, France, Germany) plus 3 smaller 30--50 cm educational/public outreach telescopes (Romania and Germany) adding about 1,000 observed NEAs; and ii) astrometry obtained from data mining of 4 major image archives (ESO/MPG WFI, INT WFC, CFHTLS Megacam and Subaru SuprimeCam) adding about 500 NEAs recovered in archival images. Among the highlights, about 100 NEAs, PHAs and VIs were observed, recovered or precovered in archives at their second opposition (up to about 15 years away from discovery) or have their orbital arc much extended, and a few VIs and PHAs were eliminated. Incidentally, about 15,000 positions of almost 2,000 known MBAs were reported (mostly in the INT, ESO/MPG and Blanco large fields). About 40 new (one night) NEO candidates and more than 2,000 (one night) unknown MBAs were reported, including about 150 MBAs credited as EURONEAR discoveries. Based on the INT and Blanco data we derived some statistics about the MBA and NEA population observable with 2m and 4m telescopes, proposing a

  15. Desert RATS 2011: Near-Earth Asteroid Human Exploration Operations

    Science.gov (United States)

    Abercromby, Andrew; Gernhardt, Michael L.; Chappel, Steve

    2012-01-01

    The Desert Research and Technology Studies (D-RATS) 2011 field test involved the planning and execution of a series of exploration scenarios under operational conditions similar to those that would be expected during a human exploration mission to a near-Earth asteroid (NEA). The focus was on understanding the operations tempo during simulated NEA exploration and the implications of communications latency and limited data bandwidth. Anchoring technologies and sampling techniques were not evaluated due to the immaturity of those technologies and the inability to meaningfully test them at D-RATS. Reduced gravity analogs and simulations are being used to fully evaluate Multi-Mission Space Exploration Vehicle (MMSEV) and extravehicular (EVA) operations and interactions in near-weightlessness at a NEA as part of NASA s integrated analogs program. Hypotheses were tested by planning and performing a series of 1-day simulated exploration excursions comparing test conditions all of which involved a single Deep Space Habitat (DSH) and either zero, one, or two MMSEVs; three or four crewmembers; one of two different communications bandwidths; and a 100-second roundtrip communications latency between the field site and Houston. Excursions were executed at the Black Point Lava Flow test site with a Mission Control Center and Science Support Room at Johnson Space Center (JSC) being operated with 100-second roundtrip communication latency to the field. Crews were composed of astronauts and professional field geologists and teams of Mission Operations, Science, and Education & Public Outreach (EPO) experts also supported the mission simulations each day. Data were collected separately from the Crew, Mission Operations, Science, and EPO teams to assess the test conditions from multiple perspectives. For the operations tested, data indicates practically significant benefits may be realized by including at least one MMSEV and by including 4 versus 3 crewmembers in the NEA exploration

  16. Cometary Activity in Near-Earth Asteroid Don Quixote

    NARCIS (Netherlands)

    Mommert, M.; Hora, J. L.; Harris, A. W.; Reach, W. T.; Mueller, M.; Thomas, C. A.; Emery, J. P.; Trilling, D. E.; Delbo', M.; Smith, H.

    2013-01-01

    The near-Earth object (NEO) population is thought to comprise a number of "dormant" short-period comets [1]. One of the most promising NEO candidates for a cometary origin is (3552) Don Quixote, due to its comet-like orbit and albedo. We present the discovery of cometary activity in (3552) Don

  17. Assessing the physical nature of near-Earth asteroids through their dynamical histories

    CERN Document Server

    Fernández, Julio A; Gallardo, Tabaré; Gutiérrez, Jorge N

    2014-01-01

    We analyze a sample of 139 near-Earth asteroids (NEAs), defined as those that reach perihelion distances $q 4.8$ au), having Tisserand parameters $2 4.8$ au of cometary origin, but it could be even lower if the NEAs in unstable orbits listed before turn out to be {\\it bona fide} asteroids from the main belt.

  18. ExploreNEOs. VIII. Dormant Short-period Comets in the Near-Earth Asteroid Population

    NARCIS (Netherlands)

    Mommert, M.; Harris, A. W.; Mueller, M.; Hora, J. L.; Trilling, D. E.; Bottke, W. F.; Thomas, C. A.; Delbo, M.; Emery, J. P.; Fazio, G.; Smith, H. A.

    2015-01-01

    We perform a search for dormant comets, asteroidal objects of cometary origin, in the near-Earth asteroid (NEA) population based on dynamical and physical considerations. Our study is based on albedos derived within the ExploreNEOs program and is extended by adding data from NEOWISE and the Akari as

  19. Trajectory and physical properties of near-Earth asteroid 2009 BD

    NARCIS (Netherlands)

    Chesley, Steven R.; Mommert, Michael; Hora, Joseph L.; Farnocchia, Davide; Trilling, David E.; Vokrouhlický, David; Mueller, Michael; Harris, Alan W; Smith, Howard Alan; Fazio, Giovanni G.

    2014-01-01

    We analyze the trajectory of near-Earth asteroid 2009 BD, which is a candidate target of the NASA Asteroid Robotic Retrieval Mission (ARRM). The small size of 2009 BD and its Earth-like orbit pose challenges to understanding the dynamical properties of 2009 BD. In particular, nongravitational pertur

  20. Trajectory and physical properties of near-Earth asteroid 2009 BD

    NARCIS (Netherlands)

    Farnocchia, D.; Mommert, M.; Hora, J. L.; Chesley, S. R.; Vokrouhlický, D.; Trilling, D. E.; Mueller, M.; Harris, A. W.; Smith, H. A.; Fazio, G. G.; Knežević, Zoran; Lemaitre, Anne

    2014-01-01

    We analyze the trajectory of near-Earth asteroid 2009~BD, which is a candidate target of the NASA Asteroid Redirect Mission. The small size of 2009 BD and its Earth-like orbit pose challenges to understanding the dynamical properties of 2009 BD. In particular, nongravitational perturbations, such as

  1. Trajectory and physical properties of near-Earth asteroid 2009 BD

    NARCIS (Netherlands)

    Chesley, Steven R.; Mommert, Michael; Hora, Joseph L.; Farnocchia, Davide; Trilling, David E.; Vokrouhlický, David; Mueller, Michael; Harris, Alan W; Smith, Howard Alan; Fazio, Giovanni G.

    2014-01-01

    We analyze the trajectory of near-Earth asteroid 2009 BD, which is a candidate target of the NASA Asteroid Robotic Retrieval Mission (ARRM). The small size of 2009 BD and its Earth-like orbit pose challenges to understanding the dynamical properties of 2009 BD. In particular, nongravitational

  2. Trajectory and physical properties of near-Earth asteroid 2009 BD

    NARCIS (Netherlands)

    Farnocchia, D.; Mommert, M.; Hora, J. L.; Chesley, S. R.; Vokrouhlický, D.; Trilling, D. E.; Mueller, M.; Harris, A. W.; Smith, H. A.; Fazio, G. G.; Knežević, Zoran; Lemaitre, Anne

    2014-01-01

    We analyze the trajectory of near-Earth asteroid 2009~BD, which is a candidate target of the NASA Asteroid Redirect Mission. The small size of 2009 BD and its Earth-like orbit pose challenges to understanding the dynamical properties of 2009 BD. In particular, nongravitational perturbations, such as

  3. ExploreNEOs. VIII. Dormant Short-period Comets in the Near-Earth Asteroid Population

    NARCIS (Netherlands)

    Mommert, M.; Harris, A. W.; Müller, M.; Hora, J. L.; Trilling, D. E.; Bottke, W. F.; Thomas, C. A.; Delbo, M.; Emery, J. P.; Fazio, G.; Smith, H. A.

    2015-01-01

    We perform a search for dormant comets, asteroidal objects of cometary origin, in the near-Earth asteroid (NEA) population based on dynamical and physical considerations. Our study is based on albedos derived within the ExploreNEOs program and is extended by adding data from NEOWISE and the Akari

  4. Properties of the moon, Mars, Martian satellites, and near-earth asteroids

    Science.gov (United States)

    Taylor, Jeffrey G.

    1989-01-01

    Environments and surface properties of the moon, Mars, Martian satellites, and near-earth asteroids are discussed. Topics include gravity, atmospheres, surface properties, surface compositions, seismicity, radiation environment, degradation, use of robotics, and environmental impacts. Gravity fields vary from large fractions of the earth's field such as 1/3 on Mars and 1/6 on the moon to smaller fractions of 0.0004 g on an asteroid 1 km in diameter. Spectral data and the analogy with meteor compositions suggest that near-earth asteroids may contain many resources such as water-rich carbonaceous materials and iron-rich metallic bodies. It is concluded that future mining and materials processing operations from extraterrestrial bodies require an investment now in both (1) missions to the moon, Mars, Phobos, Deimos, and near-earth asteroids and (2) earth-based laboratory research in materials and processing.

  5. Near-Earth-object survey progress and population of small near-Earth asteroids

    Science.gov (United States)

    Harris, A.

    2014-07-01

    Estimating the total population vs. size of NEAs and the completion of surveys is the same thing since the total population is just the number discovered divided by the estimated completion. I review the method of completion estimation based on ratio of re-detected objects to total detections (known plus new discoveries). The method is quite general and can be used for population estimations of all sorts, from wildlife to various classes of solar system bodies. Since 2001, I have been making estimates of population and survey progress approximately every two years. Plotted below, left, is my latest estimate, including NEA discoveries up to August, 2012. I plan to present an update at the meeting. All asteroids of a given size are not equally easy to detect because of specific orbital geometries. Thus a model of the orbital distribution is necessary, and computer simulations using those orbits need to establish the relation between the raw re-detection ratio and the actual completion fraction. This can be done for any sub-group population, allowing to estimate the population of a subgroup and the expected current completion. Once a reliable survey computer model has been developed and ''calibrated'' with respect to actual survey re-detections versus size, it can be extrapolated to smaller sizes to estimate completion even at very small size where re-detections are rare or even zero. I have recently investigated the subgroup of extremely low encounter velocity NEAs, the class of interest for the Asteroid Redirect Mission (ARM), recently proposed by NASA. I found that asteroids of diameter ˜ 10 m with encounter velocity with the Earth lower than 2.5 km/sec are detected by current surveys nearly 1,000 times more efficiently than the general background of NEAs of that size. Thus the current completion of these slow relative velocity objects may be around 1%, compared to 10^{-6} for that size objects of the general velocity distribution. Current surveys are nowhere near

  6. Small Near-Earth Asteroids as a Source of Meteorites

    CERN Document Server

    Borovička, Jiří; Brown, Peter

    2015-01-01

    Small asteroids intersecting Earth's orbit can deliver extraterrestrial rocks to the Earth, called meteorites. This process is accompanied by a luminous phenomena in the atmosphere, called bolides or fireballs. Observations of bolides provide pre-atmospheric orbits of meteorites, physical and chemical properties of small asteroids, and the flux (i.e. frequency of impacts) of bodies at the Earth in the centimeter to decameter size range. In this chapter we explain the processes occurring during the penetration of cosmic bodies through the atmosphere and review the methods of bolide observations. We compile available data on the fireballs associated with 22 instrumentally observed meteorite falls. Among them are the heterogeneous falls Almahata Sitta (2008 TC$_3$) and Bene\\v{s}ov, which revolutionized our view on the structure and composition of small asteroids, the P\\v{r}\\'{\\i}bram-Neuschwanstein orbital pair, carbonaceous chondrite meteorites with orbits on the asteroid-comet boundary, and the Chelyabinsk fal...

  7. Radar Observations and the Shape of Near-Earth Asteroid 2008 EV5

    CERN Document Server

    Busch, Michael W; Benner, Lance A M; Brozovic, Marina; Giorgini, Jon D; Jao, Joseph S; Scheeres, Daniel J; Magri, Christopher; Nolan, Michael C; Howell, Ellen S; Taylor, Patrick A; Margot, Jean-Luc; Brisken, Walter

    2011-01-01

    We observed the near-Earth asteroid 2008 EV5 with the Arecibo and Goldstone planetary radars and the Very Long Baseline Array during December 2008. EV5 rotates retrograde and its overall shape is a 400 /pm 50 m oblate spheroid. The most prominent surface feature is a ridge parallel to the asteroid's equator that is broken by a concavity 150 m in diameter. Otherwise the asteroid's surface is notably smooth on decameter scales. EV5's radar and optical albedos are consistent with either rocky or stony-iron composition. The equatorial ridge is similar to structure seen on the rubble-pile near-Earth asteroid (66391) 1999 KW4 and is consistent with YORP spin-up reconfiguring the asteroid in the past. We interpret the concavity as an impact crater. Shaking during the impact and later regolith redistribution may have erased smaller features, explaining the general lack of decameter-scale surface structure.

  8. Near Earth asteroid resource utilisation for large in-orbit reflectors

    Science.gov (United States)

    McInnes, C. R.

    2016-11-01

    The resources offered by the family of near Earth asteroids could provide bulk materials to support future space science ventures, both crewed missions and space-based astronomy. Using low-energy transfer trajectories small near Earth asteroids could be captured directly, or their material resources returned to Earth orbit or the Lagrange points. With novel fabrication methods, such as additive layer manufacturing, large-scale space structures including optical and radio telescopes could in principle be assembled from such resources. Indeed, with bulk materials readily available, very large numbers of structures could be fabricated in-situ for interferometry applications.

  9. The problem of the near-earth asteroids encountering the earth

    Institute of Scientific and Technical Information of China (English)

    季江徽[1; 刘林[2

    2000-01-01

    The asteroids are the most important small bodies in the solar system, while the movement of the near-earth-asteroids (NEAs) is specially concerned by the world. The focus on these asteroids is that they encounter the earth. The orbital evolution of this kind of asteroid is studied by analyzing and comparing them; reasonable dynamical models and corresponding algorithm are given, and the formal numbered NEAs are calculated. The results of the minimal distance and the very close-approach time with the earth agree well with those announced by the Minor Planet Center (MFC).

  10. The problem of the near-earth asteroids encountering the earth

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The asteroids are the most important small bodies in the solar system, while the movement of the near-earth-asteroids (NEAs) is specially concerned by the world. The focus on these asteroids is that they encounter the earth. The orbital evolution of this kind of asteroid is studied by analyzing and comparing them; reasonable dynamical models and corresponding algorithm are given, and the formal numbered NEAs are calculated. The results of the minimal distance and the very close-approach time with the earth agree well with those announced by the Minor Planet Center (MPC).

  11. Spectral properties of near-Earth and Mars-crossing asteroids using Sloan photometry

    Science.gov (United States)

    Carry, B.; Solano, E.; Eggl, S.; DeMeo, F. E.

    2016-04-01

    The nature and origin of the asteroids orbiting in near-Earth space, including those on a potentially hazardous trajectory, is of both scientific interest and practical importance. We aim here at determining the taxonomy of a large sample of near-Earth and Mars-crosser asteroids and analyze the distribution of these classes with orbit. We use this distribution to identify the source regions of near-Earth objects and to study the strength of planetary encounters to refresh asteroid surfaces. We measure the photometry of these asteroids over four filters at visible wavelengths on images taken by the Sloan Digital Sky Survey (SDSS). These colors are used to classify the asteroids into a taxonomy consistent with the widely used Bus-DeMeo taxonomy (DeMeo et al. [2009]. Icarus 202, 160-180) based on visible and near-infrared spectroscopy. We report here on the taxonomic classification of 206 near-Earth and 776 Mars-crosser asteroids determined from SDSS photometry, representing an increase of 40% and 663% of known taxonomy classifications in these populations. Using the source region mapper by Greenstreet et al. (Greenstreet, S., Ngo, H., Gladman, B. [2012]. Icarus, 217, 355-366), we compare for the first time the taxonomic distribution among near-Earth and main-belt asteroids of similar diameters. Both distributions agree at the few percent level for the inner part of the main belt and we confirm this region as a main source of near-Earth objects. The effect of planetary encounters on asteroid surfaces are also studied by developing a simple model of forces acting on a surface grain during planetary encounter, which provides the minimum distance at which a close approach should occur to trigger resurfacing events. By integrating numerically the orbit of the 519 S-type and 46 Q-type asteroids in our sample back in time for 500,000 years and monitoring their encounter distance with Venus, Earth, Mars, and Jupiter, we seek to understand the conditions for resurfacing

  12. Peculiar Betulia Re-visited: A Near-Earth Asteroid with a Bare-Rock Surface?

    NARCIS (Netherlands)

    Harris, A. W.; Mueller, M.; Delbo, M.; Bus, S. J.

    2005-01-01

    The small C-type asteroid (1580) Betulia is an unusual near-Earth object (NEO) with a lightcurve that changes dramatically with changing solar phase angle, presumably due to a highly irregular shape and/or unusual topographic features. Earlier thermal-infrared observations indicated a surface of hig

  13. Characterization of Near-Earth Asteroid 2009 KC3 from Radar and Thermal Infrared Observations

    NARCIS (Netherlands)

    Taylor, Patrick A.; Howell, E. S.; Nolan, M. C.; Benner, L. A. M.; Brozovic, M.; Giorgini, J. D.; Vervack, R. J.; Fernandez, Y. R.; Magri, C.; Mueller, M.

    2010-01-01

    We will report on the size, shape, spin state, and reflective and thermal properties of C-type, Apollo-class, potentially hazardous, near-Earth asteroid 2009 KC3 (a = 3.2 AU, e = 0.7, i = 10 deg). This object was discovered by the Siding Spring Survey in May 2009 and subsequently observed in the lat

  14. Near Earth Asteroid Rotational Analysis by Astronomical Research Institute: 2015 November thru 2016 August

    Science.gov (United States)

    Linder, Tyler R.; Puckett, Andrew; Holmes, Robert; Nowinski, Matt; Hardersen, Paul; Haislip, Josh; Reichart, Dan

    2017-04-01

    Photometric observations of six near-Earth asteroids (NEA) and one Mars-crosser (MC) were made in 2015 and 2016. We report on the analysis of the data obtained for NEAs (10150) 1994 PN, (88263) 2001 KQ1, (348400) 2005 JF21, (357024) 1999 YR14, (470510) 2008 CJ116, and 2016 LX48 and the Mars-crosser (41588) 2000 SC46.

  15. Lightcurve Analysis of the Near-Earth Asteroid 2016 NL15

    Science.gov (United States)

    Warner, Brian D.; Aznar Macias, Amadeo; Sota Ballno, Alfredo

    2017-04-01

    CCD photometric observations of the near-Earth asteroid 2016 NL15 were made in 2016 mid-December. A collaboration of three observers at widely-separated longitudes proved critical in finding the synodic period of 23.22 h, nearly commensurate with an Earth day.

  16. Optimal Flight to Near-Earth Asteroids with Using Electric Propulsion and Gravity Maneuvers

    Science.gov (United States)

    Chernov, A. V.

    Optimal space flight to near-Earth asteroid for deflection asteroids from the Earth and prevention their possible collision is investigated. The deflection is realized by means of impact-kinetic effect of the spacecraft on the asteroid and changing the asteroid orbit. The effectiveness of this method for preventing asteroid-Earth collision is estimated by means of optimal space flights, which are found. The flight of spacecraft (SC) is realized by means of using electric propulsion system. To increase effectiveness the optimal gravity maneuvers of spacecraft near Mars and Venus are using. Criterion of the space flight optimization is maximal deflection of the asteroid from the Earth at the moment of asteroid-Earth nearest approach. For determination of optimal trajectories the maximum Pontrjagin principle is used. It is assumed that the thrust of electric propulsion is unrestricted or corresponding to electric engine SPT-140 with solar battery as energy source. The technique of choice of first approximation for optimal trajectory determination on base of search optimal trajectories in more simple statement is used. The optimal trajectories are determined for wide ranges of the space flight times to near-Earth asteroids with different orbit elements. A comparison with a case of the space flight using a high thrust only or without gravity-assisted maneuvers is carried out.

  17. PANIC - A surface science package for the in situ characterization of a near-Earth asteroid

    CERN Document Server

    Schindler, Karsten; Reddy, Vishnu; Weber, Andreas; Gruska, Stefan; Fasoulas, Stefanos

    2016-01-01

    This paper presents the results of a mission concept study for an autonomous micro-scale surface lander also referred to as PANIC - the Pico Autonomous Near-Earth Asteroid In Situ Characterizer. The lander is based on the shape of a regular tetrahedron with an edge length of 35 cm, has a total mass of approximately 12 kg and utilizes hopping as a locomotion mechanism in microgravity. PANIC houses four scientific instruments in its proposed baseline configuration which enable the in situ characterization of an asteroid. It is carried by an interplanetary probe to its target and released to the surface after rendezvous. Detailed estimates of all critical subsystem parameters were derived to demonstrate the feasibility of this concept. The study illustrates that a small, simple landing element is a viable alternative to complex traditional lander concepts, adding a significant science return to any near-Earth asteroid (NEA) mission while meeting tight mass budget constraints.

  18. Human health and performance considerations for near earth asteroids (NEA)

    Science.gov (United States)

    Steinberg, Susan; Kundrot, Craig; Charles, John

    2013-11-01

    Humans are considered as a system in the design of any deep space exploration mission. The addition of many potential near asteroid (NEA) destinations to the existing multiple mission architecture for Lunar and Mars missions increases the complexity of human health and performance issues that are anticipated for exploration of space. We suggest that risks to human health and performance be analyzed in terms of the 4 major parameters related to multiple mission architecture: destination, duration, distance and vehicle design. Geological properties of the NEA will influence design of exploration tasks related to sample handling and containment, and extravehicular activity (EVA) capabilities including suit ports and tools. A robotic precursor mission that collects basic information on NEA surface properties would reduce uncertainty about these aspects of the mission as well as aid in mission architecture and exploration task design. Key mission parameters are strongly impacted by duration and distance. The most critical of these is deep-space radiation exposure without even the temporary shielding of a nearby large planetary body. The current space radiation permissible exposure limits (PEL) limits mission duration to 3-10 months depending on age, gender and stage of the solar cycle. Duration also impacts mission architectures including countermeasures for bone, muscle, and cardiovascular atrophy during continuous weightlessness; and behavioral and psychological issues resulting from isolation and confinement. Distance affects communications and limits abort and return options for a NEA mission. These factors are anticipated to have important effects on crew function and autonomous operations, as well as influence medical capability, supplies and training requirements of the crew. The design of a habitat volume that can maintain the physical and psychological health of the crew and support mission operations with limited intervention from earth will require an

  19. A Spectroscopic And Photometric Survey Of Selected Near-earth Asteroids: Results From 2008-2012.

    Science.gov (United States)

    Hicks, Michael D.; Lawrence, K. J.; Somers, J.; Teague, S.; Strojia, C.; Dombroski, D.; Davtyan, T.; Barajas, T.; Truong, T.; McCormack, M.; Gerhart, C.; Garcia, K.; Rhoades, H.; Mayes, D.; Shitanishi, J.; Foster, J.; McAuley, A.

    2012-10-01

    Over the past four years we have used the dual-channel optical spectrometer (DBSP) at the Palomar 200-inch telescope (P200) to collect low-resolution spectroscopy of Near-Earth Asteroids (NEAs) and have been awarded, on average, three nights per semester. Additionally, we have ample access to the JPL Table Mountain 0.6-m (TMO) telescope for time-resolved Bessel BVRI photometry. Undergraduate students from the CURE program (Consortium for Undergraduate Research Experience) have provided a large fraction of the observing effort at TMO. With these two telescopes, we strove to characterize all bright (VEarth asteroids (as potential mission targets). In this paper we will present our observational results for 150 NEAs. Our data products are diverse, and can include taxonomic classification, broad-band colors, rotational period, solar phase behavior and absolute magnitude, and 3-d shape/pole models derived from lightcurve inversion. We will discuss the variability between main-belt and near-Earth spectral families, quantify differences between PHA and background near-Earth populations, and present our first attempts to generate a spectral photometry using solely near-Earth asteroids. This research was funded by NASA. The student participation was supported by the National Science Foundation under REU grant 0852088 to Cal State LA.

  20. Dynamics of asteroids and near-Earth objects from Gaia Astrometry

    CERN Document Server

    Bancelin, D; Thuillot, W

    2016-01-01

    Gaia is an astrometric mission that will be launched in spring 2013. There are many scientific outcomes from this mission and as far as our Solar System is concerned, the satellite will be able to map thousands of main belt asteroids (MBAs) and near-Earth objects (NEOs) down to magnitude < 20. The high precision astrometry (0.3-5 mas of accuracy) will allow orbital improvement, mass determination, and a better accuracy in the prediction and ephemerides of potentially hazardous asteroids (PHAs). We give in this paper some simulation tests to analyse the impact of Gaia data on known asteroids' orbit, and their value for the analysis of NEOs through the example of asteroid (99942) Apophis. We then present the need for a follow-up network for newly discovered asteroids by Gaia, insisting on the synergy of ground and space data for the orbital improvement.

  1. Direct and indirect capture of near-Earth asteroids in the Earth-Moon system

    Science.gov (United States)

    Tan, Minghu; McInnes, Colin; Ceriotti, Matteo

    2017-09-01

    Near-Earth asteroids have attracted attention for both scientific and commercial mission applications. Due to the fact that the Earth-Moon L1 and L2 points are candidates for gateway stations for lunar exploration, and an ideal location for space science, capturing asteroids and inserting them into periodic orbits around these points is of significant interest for the future. In this paper, we define a new type of lunar asteroid capture, termed direct capture. In this capture strategy, the candidate asteroid leaves its heliocentric orbit after an initial impulse, with its dynamics modeled using the Sun-Earth-Moon restricted four-body problem until its insertion, with a second impulse, onto the L2 stable manifold in the Earth-Moon circular restricted three-body problem. A Lambert arc in the Sun-asteroid two-body problem is used as an initial guess and a differential corrector used to generate the transfer trajectory from the asteroid's initial obit to the stable manifold associated with Earth-Moon L2 point. Results show that the direct asteroid capture strategy needs a shorter flight time compared to an indirect asteroid capture, which couples capture in the Sun-Earth circular restricted three-body problem and subsequent transfer to the Earth-Moon circular restricted three-body problem. Finally, the direct and indirect asteroid capture strategies are also applied to consider capture of asteroids at the triangular libration points in the Earth-Moon system.

  2. More than 160 near Earth asteroids observed in the EURONEAR network

    Science.gov (United States)

    Birlan, M.; Vaduvescu, O.; Tudorica, A.; Sonka, A.; Nedelcu, A.; Galad, A.; Colas, F.; Pozo N., F.; Barr D., A.; Toma, R.; Comsa, I.; Rocher, P.; Lainey, V.; Vidican, D.; Asher, D.; Opriseanu, C.; Vancea, C.; Colque, J. P.; Soto, C. P.; Rekola, R.; Unda-Sanzana, E.

    2010-02-01

    Context. The EUROpean Near Earth Asteroid Research (EURONEAR) is a network which envisions to bring some European contributions into the general context traced by the Spaceguard Foundation which was carried out during the last 15 years mainly by the US with some modest European and amateur contributions. Aims: The number of known near Earth asteroids (NEAs) and potentially hazardous asteroids (PHAs) has increased tremendously, mainly thanks to five major surveys all focused on the discovery of new bodies. But also other facilities are required to follow-up and improvement the orbital parameters and to study the physical properties of the known bodies. These goals are better achieved by a co-ordinated network such as EURONEAR. Methods: Astrometry is mandatory in order to acquire the positional information necessary to define and improve orbits of NEAs and PHAs and to study their trajectories through the solar system, especially in the vicinity of Earth. Photometry is required to derive some physical information about NEAs and PHAs. In order to achieve these objectives, the main method of research of the EURONEAR is the follow-up programme of objects selected by a few criteria, carried out mostly at 1 m-class telescopes endowed with medium and large field cameras. Results: 162 NEAs summing more than 1500 individual positions were observed for a total time of 55 nights in both visiting mode and regular runs using nine telescopes located in four countries. The observations were reduced promptly and reported to the Minor Planet Centre (MPC) which validated and included them in the MPC and NEODyS databases following the improvement of their orbital elements. For one binary NEA we acquired photometry and were able to determine its orbital and rotational periods. Complementary to the follow-up work, as many as 500 unknown moving objects consistent with new Main Belt asteroids and one possible NEA were discovered in the analyzed fields. Conclusions: Our positions present 1

  3. Momentum Management for the NASA Near Earth Asteroid Scout Solar Sail Mission

    Science.gov (United States)

    Heaton, Andrew; Diedrich, Benjamin L.; Orphee, Juan; Stiltner, Brandon; Becker, Christopher

    2017-01-01

    The Momentum Management (MM) system is described for the NASA Near Earth Asteroid Scout (NEA Scout) cubesat solar sail mission. Unlike many solar sail mission proposals that used solar torque as the primary or only attitude control system, NEA Scout uses small reaction wheels (RW) and a reaction control system (RCS) with cold gas thrusters, as described in the abstract "Solar Sail Attitude Control System for Near Earth Asteroid Scout Cubesat Mission." The reaction wheels allow fine pointing and higher rates with low mass actuators to meet the science, communication, and trajectory guidance requirements. The MM system keeps the speed of the wheels within their operating margins using a combination of solar torque and the RCS.

  4. Searching for Brazil Nuts on Q-type near-Earth Asteroids

    Science.gov (United States)

    MacLennan, Eric M.; Emery, Joshua P.; Rozitis, Benjamin

    2016-10-01

    Q-type asteroids, the best spectral analogs of ordinary chondrite meteorites have only been definitively detected in near-Earth space. S-type asteroids, the space weathered counterparts of Q-types, however, are common, indicating that surfaces exposed to the space environment are rapidly weathered. Nevertheless, the existence of Q-type asteroids is evidence that one or more processes act to freshen asteroid surfaces, overturning the regolith to expose the un-weathered material that lies beneath. Nearly all Q-type near-Earth asteroids have been shown to currently or recently exist in orbits that bring them within close proximity to at least one terrestrial planet (i.e. a few planetary radii away). This observation has been used to infer that tidal interactions during close planetary encounters cause regolith mobilization on these bodies. This mechanism may lead to particle size segregation on the surface and interior of these bodies, particularly the sorting of large boulders to the surface. Because a large number of boulders raises the average surface thermal inertia, we hypothesize that the thermal inertia of Q-type asteroids are systematically larger than the average near-Earth asteroid population.To test this hypothesis, we determine the thermal inertia of approximately one dozen Q-type near-Earth asteroids from measurements of their thermal emission. The targets for this study are selected based on known rotation periods and observations that are made at pre- and post-opposition, with a large difference in solar phase angle. This observing geometry is crucial in constraining thermal inertia, which influences the surficial diurnal temperature variation and thus the thermal emission as a function of phase angle. We have been acquiring observations at 3.6 and 4.5 μm with the InfraRed Array Camera (IRAC) on the Spitzer Space Telescope. At these wavelengths, the measured flux is generally dominated by thermal flux, but may contain a component of reflected flux. A

  5. Spectral properties of near-Earth and Mars-crossing asteroids using Sloan photometry

    CERN Document Server

    Carry, Benoit; Eggl, Siegfried; DeMeo, Francesca E

    2016-01-01

    The nature and origin of the asteroids orbiting in near-Earth space, including those on a potentially hazardous trajectory, is of both scientific interest and practical importance. We aim here at determining the taxonomy of a large sample of near-Earth (NEA) and Mars-crosser (MC) asteroids and analyze the distribution of these classes with orbit. We use this distribution to identify their source regions and to study the strength of planetary encounters to refresh asteroid surfaces. We measure the photometry of these asteroids over four filters at visible wavelengths on images taken by the SDSS. These colors are used to classify the asteroids into a taxonomy consistent with the widely used Bus-DeMeo taxonomy based on spectroscopy. We report here on the taxonomic classification of 206 NEAs and 776 MCs determined from SDSS photometry, representing an increase of 40% and 663% of known taxonomy classifications in these populations. Using the source region mapper by Greenstreet et al. (2012), we compare the taxonom...

  6. Yarkovsky Effect on Small Near-Earth Asteroids: Mathematical Formulation and Examples

    Science.gov (United States)

    Vokrouhlický, D.; Milani, A.; Chesley, S. R.

    2000-11-01

    The Yarkovsky effect is a subtle nongravitational phenomenon related to the anisotropic thermal emission of Solar System objects. Its importance has been recently demonstrated in relation to the transport of material from the main asteroid belt (both to explain the origin of near-Earth asteroids and some properties of meteorites) and also in relation to the aging processes of the asteroid families. However, unlike the case of the artificial satellites, the Yarkovsky effect has never been measured or detected in the motion of natural bodies in the Solar System. In this paper, we investigate the possibility of detecting the Yarkovsky effect via precise orbit determination of near-Earth asteroids. Such a detection is feasible only with the existence of precise radar astrometry at multiple apparitions. Since the observability of the Yarkovsky perturbation accumulates quadratically with time the time span between radar observations is a critical factor. Though the current data do not clearly indicate the Yarkovsky effect in the motion of these bodies, we predict that the next apparition of several asteroids (in particular, 6489 Golevka, 1620 Geographos, and possibly 1566 Icarus) might reveal its existence. Moreover, we show that the Yarkovsky effect may play a very important role in the orbit determination of small, but still observable, bodies like 1998 KY 26. If carefully followed, this body may serve as a superb probe of the Yarkovsky effect in its next close approach to the Earth in June 2024.

  7. Near-Earth Asteroids as Possible Parent Bodies of Meteor Streams

    Directory of Open Access Journals (Sweden)

    M.G. Sokolova

    2016-12-01

    Full Text Available The genetic relationship of meteor streams with near-Earth asteroids (NEAs is being actively studied. A genetic link with the asteroid is possible only for streams in which meteoroids have the geocentric speed smaller than 50 km/s, thereby meaning the proportionality of their orbits with the orbits of asteroids. To date, there are about 40 such orphan streams with unknown parent bodies. In the paper, NEA groups (Aten, Apollo, Amor, and Atira have been considered from the perspective of possible search for the parent bodies of meteor streams among them. The groups have been compared based on the following parameters: eccentricity of asteroid orbits, as well as size and chemical composition of asteroids. Currently, it is considered that the surface of asteroids with elongated orbits is subjected to temperature fall: it is heated in perihelion and cooled in aphelion. Due to small orbital periods around the Sun (about 2–4 years, this may lead to formation of meteoroid clusters. Therefore, comparison of asteroids by their orbit shape and physicochemical parameters enables us to distinguish between NEA groups of asteroids and the Apollo group as most probable candidates to search for the parent bodies of meteor streams among NEAs. Unfortunately, finding physicochemical parameters poses great difficulties, since they are only detectable for some asteroids. At the same time, it is impossible to study asteroids dynamics, evolution, and relation with other bodies of the Solar system, as well as to realistically assess the impact of NEAs and products of their disintegration collision with the Earth and to develop systems of anti-asteroid protection without knowing the following parameters of asteroids: mineralogical composition, density, size, and accurate mass.

  8. Near-infrared thermal emission from near-Earth asteroids: Aspect-dependent variability

    CERN Document Server

    Moskovitz, Nicholas A; DeMeo, Francesca E; Binzel, Richard P; Endicott, Thomas; Yang, Bin; Howell, Ellen S; Vervack, Ronald J; Fernandez, Yanga R

    2016-01-01

    Here we explore a technique for constraining physical properties of near-Earth asteroids (NEAs) based on variability in thermal emission as a function of viewing aspect. We present case studies of the low albedo, near-Earth asteroids (285263) 1998 QE2 and (175706) 1996 FG3. The Near-Earth Asteroid Thermal Model (NEATM) is used to fit signatures of thermal emission in near-infrared (0.8 - 2.5 micron) spectral data. This analysis represents a systematic study of thermal variability in the near-IR as a function of phase angle. The observations of QE2 imply that carefully timed observations from multiple viewing geometries can be used to constrain physical properties like retrograde versus prograde pole orientation and thermal inertia. The FG3 results are more ambiguous with detected thermal variability possibly due to systematic issues with NEATM, an unexpected prograde rotation state, or a surface that is spectrally and thermally heterogenous. This study highlights the potential diagnostic importance of high ph...

  9. ExploreNEOs. VIII. Dormant Short-period Comets in the Near-Earth Asteroid Population

    Science.gov (United States)

    Mommert, M.; Harris, A. W.; Mueller, M.; Hora, J. L.; Trilling, D. E.; Bottke, W. F.; Thomas, C. A.; Delbo, M.; Emery, J. P.; Fazio, G.; Smith, H. A.

    2015-10-01

    We perform a search for dormant comets, asteroidal objects of cometary origin, in the near-Earth asteroid (NEA) population based on dynamical and physical considerations. Our study is based on albedos derived within the ExploreNEOs program and is extended by adding data from NEOWISE and the Akari asteroid catalog. We use a statistical approach to identify asteroids on orbits that resemble those of short-period near-Earth comets (NECs) using the Tisserand parameter with respect to Jupiter, the aphelion distance, and the minimum orbital intersection distance with respect to Jupiter. From the sample of NEAs on comet-like orbits, we select those with a geometric albedo pV ≤ 0.064 as dormant comet candidates, and find that only ˜50% of NEAs on comet-like orbits also have comet-like albedos. We identify a total of 23 NEAs from our sample that are likely to be dormant short-period NECs and, based on a de-biasing procedure applied to the cryogenic NEOWISE survey, estimate both magnitude-limited and size-limited fractions of the NEA population that are dormant short-period comets. We find that 0.3%-3.3% of the NEA population with H ≤ 21, and ({9}-5+2)% of the population with diameters d ≥ 1 km, are dormant short-period NECs.

  10. The rotation state of 4015 Wilson-Harrington: Revisiting origins for the near-Earth asteroids

    Science.gov (United States)

    Osip, DAVIDJ.; Campins, H.; Schleicher, David G.

    1995-01-01

    CCD photometry performed on the comet-asteroid transition object 4015 Wilson-Harrington during its most recent apparition has provided a new rotational lightcurve with a standard double-peaked rotational period of 6.1 +/- 0.05 hr and an amplitude of 0.2 magnitudes. The size, rotation period, and lightcurve amplitude of this object are all similar to values found for near-Earth asteroids (NEA) and small main-belt asteroids. However, these values vary significantly from those of any previously well-studied cometary nuclei. In short, the range in cometary nuclear properties is greater than that indicated by the comets studied previously and although the statistics are still poor, the size and rotational properties of 4015 Wilson-Harrington do suggest that some fraction of NEAs are of cometary origin.

  11. V-type Near-Earth asteroids: dynamics, close encounters and impacts with terrestrial planets

    CERN Document Server

    Galiazzo, M A; Bancelin, D

    2016-01-01

    Asteroids colliding with planets vary in composition and taxonomical type. Among Near-Earth Asteroids (NEAs) are the V-types, basaltic asteroids that are classified via spectroscopic observations. In this work, we study the probability of V-type NEAs colliding with Earth, Mars and Venus, as well as the Moon. We perform a correlational analysis of possible craters produced by V-type NEAs. To achieve this, we performed numerical simulations and statistical analysis of close encounters and impacts between V-type NEAs and the terrestrial planets over the next 10 Myr. We find that V-type NEAs can indeed have impacts with all the planets, the Earth in particular, at an average rate of once per 12 Myr. There are four candidate craters on Earth that were likely caused by V-type NEAs.

  12. Physical characterisation of near-Earth asteroid (1620) Geographos. Reconciling radar and thermal-infrared observations

    CERN Document Server

    Rozitis, Ben

    2014-01-01

    The Yarkovsky (orbital drift) and YORP (spin state change) effects play important roles in the dynamical and physical evolution of asteroids. Thermophysical modelling of these observed effects, and of thermal-infrared observations, allows a detailed physical characterisation of an individual asteroid to be performed. We perform a detailed physical characterisation of near-Earth asteroid (1620) Geographos, a potential meteor stream source and former spacecraft target, using the same techniques as previously used in Rozitis et al. (2013) for (1862) Apollo. We use the advanced thermophysical model (ATPM) on published light-curve, radar, and thermal-infrared observations to constrain the thermophysical properties of Geographos. The derived properties are used to make detailed predictions of the Yarkovsky orbital drift and YORP rotational acceleration, which are then compared against published measurements to determine Geographos's bulk density. We find that Geographos has a thermal inertia of 340 +140/-100 J m-2 ...

  13. The Size Distribution of the Small Near Earth Asteroids from Spacewatch

    Science.gov (United States)

    Haskell, Halford; Larsen, J.

    2009-01-01

    We are currently in the process of analyzing five years of near earth asteroid detections from the Spacewatch 0.9 meter mosaic camera. These data represent images of approximately 80,000 square degrees which have been surveyed to a limiting magnitude of 21.5 using 20 second integrations. Over 1800 detections of NEAs have been made in a consistent automated fashion with attention to observing conditions. In this poster, we present a careful debiasing of the Spacewatch pointing history following the methods outlined in Jedicke, Larsen and Spahr (2003) and use the data from the survey to calculate the size distribution of small (H > 22) near earth asteroids. For these small sizes we have needed to expand the size of our survey simulations by approximately 100 orders of magnitude in order to represent very small, very hard to detect NEAs. We use the simulations to model the biases of our survey and use the actual detections to explore the size distribution. We present a detailed examination of the "dip" in the size distribution first noticed by Harris (2008) between H=19 and H= 26. Spacewatch is funded by grants from NASA's Near Earth Object Observation and Planetary Astronomy Programs, The Brinson Foundation, the estates of Richard S. Vail and Robert L. Waland and other private individuals.

  14. Near-Earth Asteroids 2006 RH120 AND 2009 BD: Proxies for Maximally Accessible Objects?

    Science.gov (United States)

    Barbee, Brent W.; Chodas, Paul W.

    2015-01-01

    NASA's Near-Earth Object Human Space Flight Accessible Targets Study (NHATS) has identified over 1,400 of the approximately 12,800 currently known near-Earth asteroids (NEAs) as more astrodynamically accessible, round-trip, than Mars. Hundreds of those approximately 1,400 NEAs can be visited round-trip for less change-in-velocity than the lunar surface, and dozens can be visited round-trip for less change-in-velocity than low lunar orbit. How accessible might the millions of undiscovered NEAs be? We probe that question by investigating the hypothesis that NEAs 2006 RH120 and 2009 BD are proxies for the most accessible NEAs we would expect to find, and describing possible future NEA population model studies.

  15. Meteoritic and Geologic Context of the Chelyabinsk Near-Earth Asteroid Air Burst (Invited)

    Science.gov (United States)

    Kring, D. A.; Swindle, T. D.; Zolensky, M. E.

    2013-12-01

    Estimating the hazards of potential near-Earth asteroid (NEA) air burst and impact cratering events have been difficult. Current estimates of blast damage (e.g., [1]) rely on uncertain impact energies for events like Sikhote-Alin (1947), Tunguska (1908), and Barringer Meteorite Crater (~50 ka). The Chelyabinsk air burst event of an LL-chondrite NEA on 15 February 2013 provides a calibration point for enhancing those assessments. U.S. Government sensors indicate the impacting NEA had a velocity of 18.6 km/s and kinetic energy ~440 kt [2] with a total energy of possibly 500 kt. Using average bulk densities of LL-chondrite falls (3.22 g/cm3) and S-class main belt asteroids (2.7 g/cm3) [3], we derive an average diameter of 18.6 and 20 m, respectively. If the density was similar to that of rubble-pile LL-chondritic NEA Itokawa (1.9 g/cm3 [4]) or rubble-pile binary NEAs (~1.5 g/cm3), then the diameter may have been as large as 22 to 24 m. The strength of impacting NEA may be limited to structural flaws, like fractures and material contrasts (e.g., [5]); indeed, fragmental meteoroids preferentially produce meteorite showers. Not surprisingly, Chelyabinsk is a brecciated LL-chondrite and cross-cut with impact melt veins that were generated by older collisional events. Impact-generated cataclasis produced a breccia of light-colored chondrule-bearing clasts with sub-millimeter-wide fractures and silicate-rich shock melt veins, some of which form melt pockets where they intersect. Those clasts are separated by thin, sub-millimeter-wide channels of dark-colored matrix and centimeter-wide swaths of vesiculated and heterogeneously quenched impact melt. Catastrophic fragmentation of these types of NEA can produce ground-level air blast effects if that fragmentation occurs at a sufficiently low altitude. Based on pre-Chelyabinsk scaling [1], blast damage over an area of 102 to 103 km2 is expected for a 440-500 kt event. The 20-meter-diameter Chelyabinsk meteoroid was composed of

  16. The Discovery of Cometary Activity in Near-Earth Asteroid (3552) Don Quixote

    CERN Document Server

    Mommert, Michael; Harris, Alan W; Reach, William T; Emery, Joshua P; Thomas, Cristina A; Mueller, Michael; Cruikshank, Dale P; Trilling, David E; Delbo', Marco; Smith, Howard A

    2013-01-01

    The near-Earth object (NEO) population, which mainly consists of fragments from collisions between asteroids in the main asteroid belt, is thought to include contributions from short-period comets as well. One of the most promising NEO candidates for a cometary origin is near-Earth asteroid (3552) Don Quixote, which has never been reported to show activity. Here we present the discovery of cometary activity in Don Quixote based on thermal-infrared observations made with the Spitzer Space Telescope in its 3.6 and 4.5 {\\mu}m bands. Our observations clearly show the presence of a coma and a tail in the 4.5 {\\mu}m but not in the 3.6 {\\mu}m band, which is consistent with molecular band emission from CO2. Thermal modeling of the combined photometric data on Don Quixote reveals a diameter of 18.4 (-0.4/+0.3) km and an albedo of 0.03 (-0.01/+0.02), which confirms Don Quixote to be the third-largest known NEO. We derive an upper limit on the dust production rate of 1.9 kg s^-1 and derive a CO2 gas production rate of (...

  17. Near-infrared thermal emission from near-Earth asteroids: Aspect-dependent variability

    Science.gov (United States)

    Moskovitz, Nicholas A.; Polishook, David; DeMeo, Francesca E.; Binzel, Richard P.; Endicott, Thomas; Yang, Bin; Howell, Ellen S.; Vervack, , Ronald J.; Fernández, Yanga R.

    2017-03-01

    Here we explore a technique for constraining physical properties of near-Earth asteroids (NEAs) based on variability in thermal emission as a function of viewing aspect. We present case studies of the low albedo, near-Earth asteroids (285263) 1998 QE2 and (175706) 1996 FG3. The Near-Earth Asteroid Thermal Model (NEATM) is used to fit signatures of thermal emission in near-infrared (0.8 - 2.5 μm) spectral data. This analysis represents a systematic study of thermal variability in the near-IR as a function of phase angle. The observations of QE2 imply that carefully timed observations from multiple viewing geometries can be used to constrain physical properties like retrograde versus prograde pole orientation and thermal inertia. The FG3 results are more ambiguous with detected thermal variability possibly due to systematic issues with NEATM, an unexpected prograde rotation state, or a surface that is spectrally and thermally heterogenous. This study highlights the potential diagnostic importance of high phase angle thermal measurements on both sides of opposition. We find that the NEATM thermal beaming parameters derived from our near-IR data tend to be of order10's of percent higher than parameters from ensemble analyses of longer wavelength data sets. However, a systematic comparison of NEATM applied to data in different wavelength regimes is needed to understand whether this offset is simply a reflection of small number statistics or an intrinsic limitation of NEATM when applied to near-IR data. With the small sample presented here, it remains unclear whether NEATM modeling at near-IR wavelengths can robustly determine physical properties like pole orientation and thermal inertia.

  18. The near-Earth asteroid population from two decades of observations

    Science.gov (United States)

    Tricarico, Pasquale

    2017-03-01

    Determining the size and orbital distribution of the population of near-Earth asteroids (NEAs) is the focus of intense research, with the most recent models converging to a population of approximately 1000 NEAs larger than 1 km and up to approximately 109 NEAs with absolute magnitude H population of NEAs is 920 ± 10, lower than other recent estimates. The population of small NEAs is estimated at (4 ± 1) × 108 for H population tracks accurately the orbital distribution of recently discovered large NEAs, and produces an estimated Earth impact rate for small NEAs in good agreement with the bolide data.

  19. Spectral and Spin Measurement of Two Small and Fast-Rotating Near-Earth Asteroids

    CERN Document Server

    Polishook, D; Lockhart, M; DeMeo, F E; Golisch, W; Bus, S J; Gulbis, A A S

    2012-01-01

    In May 2012 two asteroids made near-miss "grazing" passes at distances of a few Earth-radii: 2012 KP24 passed at nine Earth-radii and 2012 KT42 at only three Earth-radii. The latter passed inside the orbital distance of geosynchronous satellites. From spectral and imaging measurements using NASA's 3-m Infrared Telescope Facility (IRTF), we deduce taxonomic, rotational, and physical properties. Their spectral characteristics are somewhat atypical among near-Earth asteroids: C-complex for 2012 KP24 and B-type for 2012 KT42, from which we interpret the albedos of both asteroids to be between 0.10 and 0.15 and effective diameters of 20+-2 and 6+-1 meters, respectively. Among B-type asteroids, the spectrum of 2012 KT42 is most similar to 3200 Phaethon and 4015 Wilson-Harrington. Not only are these among the smallest asteroids spectrally measured, we also find they are among the fastest-spinning: 2012 KP24 completes a rotation in 2.5008+-0.0006 minutes and 2012 KT42 rotates in 3.634+-0.001 minutes.

  20. The technical and economic feasibility of mining the near-earth asteroids

    Science.gov (United States)

    Sonter, M. J.

    The Near Earth Asteroids are primary targets for resources to support space industrialization. Robust technical and economic approaches to project planning feasibility evaluation are needed to evaluate such space mining ventures. This paper discusses the technical engineering and mission-planning choices and shows how the concept of probabilistic Net Present Value can be used to optimize asteroid mining project designs. The generic mission reviewed envisages a lightweight (3 or 4 tonnes) remote (teleoperated) regolith miner or drilling rig, recovering products such as water and other volatiles using solar thermal power, and subsequently returning approximately 1000 to 2000 tonnes to Low Earth Orbit, using solar thermal rocket propulsion. Initial estimates of NPV are highly favourable for some targets.

  1. Constraining the Bulk Density of 10m-Class Near-Earth Asteroid 2012 LA

    Science.gov (United States)

    Mommert, Michael; Hora, Joseph; Farnocchia, Davide; Trilling, David; Chesley, Steve; Harris, Alan; Mueller, Migo; Smith, Howard

    2016-08-01

    The physical properties of near-Earth asteroids (NEAs) provide important hints on their origin, as well as their past physical and orbital evolution. Recent observations seem to indicate that small asteroids are different than expected: instead of being monolithic bodies, some of them instead resemble loose conglomerates of smaller rocks, so called 'rubble piles'. This is surprising, since self-gravitation is practically absent in these bodies. Hence, bulk density measurements of small asteroids, from which their internal structure can be estimated, provide unique constraints on asteroid physical models, as well as models for asteroid evolution. We propose Spitzer Space Telescope observations of 10 m-sized NEA 2012 LA, which will allow us to constrain the diameter, albedo, bulk density, macroporosity, and mass of this object. We require 30 hrs of Spitzer time to detect our target with a minimum SNR of 3 in CH2. In order to interpret our observational results, we will use the same analysis technique that we used in our successful observations and analyses of tiny asteroids 2011 MD and 2009 BD. Our science goal, which is the derivation of the target's bulk density and its internal structure, can only be met with Spitzer. Our observations will produce only the third comprehensive physical characterization of an asteroid in the 10m size range (all of which have been carried out by our team, using Spitzer). Knowledge of the physical properties of small NEAs, some of which pose an impact threat to the Earth, is of importance for understanding their evolution and estimating the potential of destruction in case of an impact, as well as for potential manned missions to NEAs for either research or potential commercial uses.

  2. Radar imaging and physical characterization of near-Earth Asteroid (162421) 2000 ET70

    Science.gov (United States)

    Naidu, Shantanu P.; Margot, Jean-Luc; Busch, Michael W.; Taylor, Patrick A.; Nolan, Michael C.; Brozovic, Marina; Benner, Lance A. M.; Giorgini, Jon D.; Magri, Christopher

    2013-09-01

    We observed near-Earth Asteroid (162421) 2000 ET70 using the Arecibo and Goldstone radar systems over a period of 12 days during its close approach to the Earth in February 2012. We obtained continuous wave spectra and range-Doppler images with range resolutions as fine as 15 m. Inversion of the radar images yields a detailed shape model with an effective spatial resolution of 100 m. The asteroid has overall dimensions of 2.6 km × 2.2 km × 2.1 km (5% uncertainties) and a surface rich with kilometer-scale ridges and concavities. This size, combined with absolute magnitude measurements, implies an extremely low albedo (∼2%). It is a principal axis rotator and spins in a retrograde manner with a sidereal spin period of 8.96 ± 0.01 h. In terms of gravitational slopes evaluated at scales of 100 m, the surface seems mostly relaxed with over 99% of the surface having slopes less than 30°, but there are some outcrops at the north pole that may have steeper slopes. Our precise measurements of the range and velocity of the asteroid, combined with optical astrometry, enables reliable trajectory predictions for this potentially hazardous asteroid in the interval 460-2813.

  3. Measurement requirements for a near-Earth asteroid impact mitigation demonstration mission

    CERN Document Server

    Wolters, Stephen D; Wells, Nigel; Saunders, Christopher; McBride, Neil

    2011-01-01

    A concept for an Impact Mitigation Preparation Mission, called Don Quijote, is to send two spacecraft to a Near-Earth Asteroid (NEA): an Orbiter and an Impactor. The Impactor collides with the asteroid while the Orbiter measures the resulting change in the asteroid's orbit, by means of a Radio Science Experiment (RSE) carried out before and after impact. Three parallel Phase A studies on Don Quijote were carried out for the European Space Agency: the research presented here reflects outcomes of the study by QinetiQ. We discuss the mission objectives with regards to the prioritisation of payload instruments, with emphasis on the interpretation of the impact. The Radio Science Experiment is described and it is examined how solar radiation pressure may increase the uncertainty in measuring the orbit of the target asteroid. It is determined that to measure the change in orbit accurately a thermal IR spectrometer is mandatory, to measure the Yarkovsky effect. The advantages of having a laser altimeter are discusse...

  4. PHYSICAL PROPERTIES OF NEAR-EARTH ASTEROID 2011 MD

    Energy Technology Data Exchange (ETDEWEB)

    Mommert, M.; Trilling, D. E. [Department of Physics and Astronomy, Northern Arizona University, P.O. Box 6010, Flagstaff, AZ 86011 (United States); Farnocchia, D.; Chesley, S. R.; Chodas, P. W. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Hora, J. L.; Smith, H. A.; Fazio, G. G. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS 65, Cambridge, MA 02138-1516 (United States); Mueller, M. [SRON Netherlands Institute for Space Research, Postbus 800, 9700-AV Groningen (Netherlands); Harris, A. W. [DLR Institute of Planetary Research, Rutherfordstrasse 2, D-12489 Berlin (Germany)

    2014-07-01

    We report on observations of near-Earth asteroid 2011 MD with the Spitzer Space Telescope. We have spent 19.9 hr of observing time with channel 2 (4.5 μm) of the Infrared Array Camera and detected the target within the 2σ positional uncertainty ellipse. Using an asteroid thermophysical model and a model of nongravitational forces acting upon the object, we constrain the physical properties of 2011 MD, based on the measured flux density and available astrometry data. We estimate 2011 MD to be (6{sub −2}{sup +4}) m in diameter with a geometric albedo of 0.3{sub −0.2}{sup +0.4} (uncertainties are 1σ). We find the asteroid's most probable bulk density to be (1.1{sub −0.5}{sup +0.7}) g cm{sup –3}, which implies a total mass of (50-350) t and a macroporosity of ≥65%, assuming a material bulk density typical of non-primitive meteorite materials. A high degree of macroporosity suggests that 2011 MD is a rubble-pile asteroid, the rotation of which is more likely to be retrograde than prograde.

  5. Measurement requirements for a Near-Earth Asteroid impact mitigation demonstration mission

    Science.gov (United States)

    Wolters, Stephen D.; Ball, Andrew J.; Wells, Nigel; Saunders, Christopher; McBride, Neil

    2011-10-01

    A concept for an Impact Mitigation Preparation Mission, called Don Quijote, is to send two spacecrafts to a Near-Earth Asteroid (NEA): an Orbiter and an Impactor. The Impactor collides with the asteroid while the Orbiter measures the resulting change in the asteroid's orbit, by means of a Radio Science Experiment (RSE) carried out before and after the impact. Three parallel Phase A studies on Don Quijote were carried out for the European Space Agency: the research presented here reflects the outcomes of the study by QinetiQ. We discuss the mission objectives with regard to the prioritisation of payload instruments, with emphasis on the interpretation of the impact. The Radio Science Experiment is described and it is examined how solar radiation pressure may increase the uncertainty in measuring the orbit of the target asteroid. It is determined that to measure the change in orbit accurately a thermal IR spectrometer is mandatory, to measure the Yarkovsky effect. The advantages of having a laser altimeter are discussed. The advantages of a dedicated wide-angle impact camera are discussed and the field-of-view is initially sized through a simple model of the impact.

  6. BILLIARDS: A Demonstration Mission for Hundred-Meter Class Near-Earth Asteroid Disruption

    Science.gov (United States)

    Marcus, Matthew; Sloane, Joshua; Ortiz, Oliver; Barbee, Brent William

    2015-01-01

    Collisions from near-Earth asteroids (NEAs) have the potential to cause widespread harm to life on Earth. The hypervelocity nature of these collisions means that a relatively small asteroid (about a quartermile in diameter) could cause a global disaster. Proposed strategies for deflecting or disrupting such a threatening asteroid include detonation of a nuclear explosive device (NED) in close proximity to the asteroid, as well as intercepting the asteroid with a hypervelocity kinetic impactor. NEDs allow for the delivery of large amounts of energy to a NEA for a given mass launched from the Earth, but have not yet been developed or tested for use in deep space. They also present safety and political complications, and therefore may only be used when absolutely necessary. Kinetic impactors require a relatively simple spacecraft compared to NEDs, but also deliver a much lower energy for a given launch mass. To date, no demonstration mission has been conducted for either case, and such a demonstration mission must be conducted prior to the need to utilize them during an actual scenario to ensure that an established, proven system is available for planetary defense when the need arises. One method that has been proposed to deliver a kinetic impactor with impact energy approaching that of an NED is the "billiard-ball" approach. This approach would involve capturing an asteroid approximately ten meters in diameter with a relatively small spacecraft (compared to the launch mass of an equivalent direct kinetic impactor), and redirecting it into the path of an Earth-threatening asteroid. This would cause an impact which would disrupt the Earth-threatening asteroid or deflect it from its Earth-crossing trajectory. The BILLIARDS Project seeks to perform a demonstration of this mission concept in order to establish a protocol that can be used in the event of an impending Earth/asteroid collision. In order to accomplish this objective, the mission must (1) rendezvous with a

  7. Next Gen NEAR: Near Earth Asteroid Human Robotic Precursor Mission Concept

    Science.gov (United States)

    Rivkin, Andrew S.; Kirby, Karen; Cheng, Andrew F.; Gold, Robert; Kelly, Daniel; Reed, Cheryl; Abell, Paul; Garvin, James; Landis, Rob

    2012-01-01

    Asteroids have long held the attention of the planetary science community. In particular, asteroids that evolve into orbits near that of Earth, called near-Earth objects (NEO), are of high interest as potential targets for exploration due to the relative ease (in terms of delta V) to reach them. NASA's Flexible Path calls for missions and experiments to be conducted as intermediate steps towards the eventual goal of human exploration of Mars; piloted missions to NEOs are such example. A human NEO mission is a valuable exploratory step beyond the Earth-Moon system enhancing capabilities that surpass our current experience, while also developing infrastructure for future mars exploration capabilities. To prepare for a human rendezvous with an NEO, NASA is interested in pursuing a responsible program of robotic NEO precursor missions. Next Gen NEAR is such a mission, building on the NEAR Shoemaker mission experience at the JHU/APL Space Department, to provide an affordable, low risk solution with quick data return. Next Gen NEAR proposes to make measurements needed for human exploration to asteroids: to demonstrate proximity operations, to quantify hazards for human exploration and to characterize an environment at a near-Earth asteroid representative of those that may be future human destinations. The Johns Hopkins University Applied Physics Laboratory has demonstrated exploration-driven mission feasibility by developing a versatile spacecraft design concept using conventional technologies that satisfies a set of science, exploration and mission objectives defined by a concept development team in the summer of 2010. We will describe the mission concept and spacecraft architecture in detail. Configuration options were compared with the mission goals and objectives in order to select the spacecraft design concept that provides the lowest cost, lowest implementation risk, simplest operation and the most benefit for the mission implementation. The Next Gen NEAR

  8. Detection of a faint fast-moving near-Earth asteroid using the synthetic tracking technique

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Chengxing; Shao, Michael; Nemati, Bijan; Werne, Thomas; Zhou, Hanying; Turyshev, Slava G.; Sandhu, Jagmit [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Hallinan, Gregg; Harding, Leon K., E-mail: chengxing.zhai@jpl.nasa.gov [Department of Astronomy, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States)

    2014-09-01

    We report a detection of a faint near-Earth asteroid (NEA) using our synthetic tracking technique and the CHIMERA instrument on the Palomar 200 inch telescope. With an apparent magnitude of 23 (H = 29, assuming detection at 20 lunar distances), the asteroid was moving at 6.°32 day{sup –1} and was detected at a signal-to-noise ratio (S/N) of 15 using 30 s of data taken at a 16.7 Hz frame rate. The detection was confirmed by a second observation 77 minutes later at the same S/N. Because of its high proper motion, the NEA moved 7 arcsec over the 30 s of observation. Synthetic tracking avoided image degradation due to trailing loss that affects conventional techniques relying on 30 s exposures; the trailing loss would have degraded the surface brightness of the NEA image on the CCD down to an approximate magnitude of 25 making the object undetectable. This detection was a result of our 12 hr blind search conducted on the Palomar 200 inch telescope over two nights, scanning twice over six (5.°3 × 0.°046) fields. Detecting only one asteroid is consistent with Harris's estimates for the distribution of the asteroid population, which was used to predict a detection of 1.2 NEAs in the H-magnitude range 28-31 for the two nights. The experimental design, data analysis methods, and algorithms are presented. We also demonstrate milliarcsecond-level astrometry using observations of two known bright asteroids on the same system with synthetic tracking. We conclude by discussing strategies for scheduling observations to detect and characterize small and fast-moving NEAs using the new technique.

  9. Radar Imaging and Physical Characterization of Near-Earth Asteroid (162421) 2000 ET70

    CERN Document Server

    Naidu, Shantanu P; Busch, Michael W; Taylor, Patrick A; Nolan, Michael C; Howell, Ellen S; Brozovic, Marina; Benner, Lance A M; Giorgini, Jon D; Magri, Christopher

    2013-01-01

    We observed near-Earth asteroid (162421) 2000 ET70 using the Arecibo and Goldstone radar systems over a period of 12 days during its close approach to the Earth in February 2012. We obtained continuous wave spectra and range-Doppler images with range resolutions as fine as 15 m. Inversion of the radar images yields a detailed shape model with an effective resolution of 100 m. The asteroid has overall dimensions of 2.6 km X 2.2 km X 2.1 km and a surface rich with kilometer-scale ridges and concavities. It is a principal axis rotator and spins in a retrograde manner with a spin period of 8.96 +/- 0.02 hours. In terms of gravitational slopes evaluated at scales of 100 m, the surface seems mostly relaxed with over 99% of the surface having slopes less than 30 degrees, but there are some outcrops at the north pole that may have steeper slopes. Our precise measurements of the range and velocity of the asteroid, combined with optical astrometry, enables reliable trajectory predictions for this potentially hazardous ...

  10. Detection of a faint fast-moving near-Earth asteroid using synthetic tracking technique

    CERN Document Server

    Zhai, Chengxing; Nemati, Bijan; Werne, Thomas A; Zhou, Hanying; Turyshev, Slava G; Sandhu, Jagmit; Hallinan, Gregg W; Harding, Leon K

    2014-01-01

    We report a detection of a faint near-Earth asteroid (NEA), which was done using our synthetic tracking technique and the CHIMERA instrument on the Palomar 200-inch telescope. This asteroid, with apparent magnitude of 23, was moving at 5.97 degrees per day and was detected at a signal-to-noise ratio (SNR) of 15 using 30 sec of data taken at a 16.7 Hz frame rate. The detection was confirmed by a second observation one hour later at the same SNR. The asteroid moved 7 arcseconds in sky over the 30 sec of integration time because of its high proper motion. The synthetic tracking using 16.7 Hz frames avoided the trailing loss suffered by conventional techniques relying on 30-sec exposure, which would degrade the surface brightness of image on CCD to an approximate magnitude of 25. This detection was a result of our 12-hour blind search conducted on the Palomar 200-inch telescope over two nights on September 11 and 12, 2013 scanning twice over six 5.0 deg x 0.043 deg fields. The fact that we detected only one NEA, ...

  11. Thermal Properties and a Revised Shape Model for Near-Earth Asteroid (162421) 2000 ET70

    Science.gov (United States)

    Marshall, Sean E.; Howell, Ellen S.; Magri, Christopher; Campbell, Donald B.; Nolan, Michael C.; Fernandez, Yanga R.; Vervack, Ronald J., Jr.; Crowell, Jenna L.; Hicks, Michael D.; Lawrence, Kenneth J.; Taylor, Patrick A.

    2016-10-01

    We present thermal properties and an improved shape model for potentially hazardous asteroid (162421) 2000 ET70. In addition to the radar data from 2000 ET70's apparition in 2012, our revised model incorporates optical lightcurves and infrared spectra that were not used for the shape model of Naidu et al. (2013). We confirm the general "clenched fist" shape of their model but find the asteroid's dimensions to be somewhat different. In particular, the lightcurves favor a model that is significantly shorter along its z-axis (rotation axis) than the model of Naidu et al. With the available data, 2000 ET70's rotation period and pole position are degenerate with each other. The radar and lightcurve data together constrain the pole direction to fall along an arc that is about twenty-five degrees long and ten degrees wide. Infrared spectra from the NASA InfraRed Telescope Facility (IRTF) provide an additional constraint on the pole. Thermophysical modeling, using our SHERMAN software, shows that only a subset of the pole directions along that arc are compatible with the infrared data. This study demonstrates the power of multiple data sets in the investigation of near-Earth asteroids.

  12. Arecibo and Goldstone Radar Imaging of Near-Earth Asteroid 2005 WC1

    Science.gov (United States)

    Lawrence, Kenneth J.; Benner, Lance A. M.; Brozovic, Marina; Jao, Joseph S.; Giorgini, Jon D.; Slade, Martin A.; Jurgens, Raymond F.; Nolan, Michael C.; Howell, Ellen S.; Taylor, Patrick A.

    2016-10-01

    We report radar observations of near-Earth asteroid 2005 WC1 that were obtained at Arecibo (2380 MHz, 13 cm) and Goldstone (8560 MHz, 3.5 cm) on 2005 December 14-15 during the asteroid's approach within 0.020 au (7.7 lunar distances). The asteroid was a strong radar target and we obtained a sequence of delay-Doppler images with resolutions as fine as 7.5 m/pixel. The radar images reveal an angular object with several pronounced facets, radar-dark regions, and an estimated diameter of ~0.4 km. The rotation of the facets in the images gives a rotation period of 2.57 h that is consistent with the estimate of 2.582 h ± 0.002 h reported by Miles et al. (private communication). 2005 WC1 has a circular polarization ratio of 1.12 ± 0.02 that is one of the highest values known, suggesting a structurally-complex near-surface at centimeter decimeter spatial scales. This work has been performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA.

  13. Thermal infrared observations of near-Earth asteroid 2002 NY40

    CERN Document Server

    Müller, T G; Schuetz, O; Pravec, P; Siebenmorgen, R

    2004-01-01

    We obtained N-band observations of the Apollo asteroid 2002 NY40 during its close Earth fly-by in August 2002 with TIMMI2 at the ESO 3.6 m telescope. The photometric measurement allowed us to derive a radiometric diameter of 0.28+/-0.03 km and an albedo of 0.34+/-0.06 through the near-Earth asteroid thermal model (NEATM) and a thermophysical model (TPM). The values are in agreement with results from radar data, visual and near-IR observations. In this first comparison between these two model approaches we found that the empirical NEATM beaming parameter $\\eta$=1.0 corresponds to a thermal inertia values of about 100 $\\mathrm{J m^{-2} s^{-0.5} K^{-1}}$ for a typical range of surface roughness, assuming an equator-on viewing angle. Our TPM analysis indicated that the surface of 2002 NY40 consists of rocky material with a thin or no dust regolith. The asteroid very likely has a prograde sense of rotation with a cold terminator at the time of our observations. Although both model approaches can fit the thermal sp...

  14. Capabilities of Earth-based Radar Facilities for Near-Earth Asteroid Observations

    Science.gov (United States)

    Naidu, Shantanu. P.; Benner, Lance. A. M.; Margot, Jean-Luc; Busch, Michael. W.; Taylor, Patrick. A.

    2016-10-01

    We evaluated the planetary radar capabilities at Arecibo, the Goldstone 70 m DSS-14 and 34 m DSS-13 antennas, the 70 m DSS-43 antenna at Canberra, the Green Bank Telescope (GBT), and the Parkes Radio Telescope in terms of their relative sensitivities and the number of known near-Earth asteroids (NEAs) detectable per year in monostatic and bistatic configurations. In the 2015 calendar year, monostatic observations with Arecibo and DSS-14 were capable of detecting 253 and 131 NEAs respectively, with signal-to-noise ratios (SNRs) greater than 30/track. Combined, the two observatories were capable of detecting 276 NEAs. Of these, Arecibo detected 77 and Goldstone detected 32, or 30% and 24% of the numbers that were possible. The two observatories detected an additional 18 and 7 NEAs respectively, with SNRs of less than 30/track. This indicates that a substantial number of potential targets are not being observed. The bistatic configuration with DSS-14 transmitting and the GBT receiving was capable of detecting about 195 NEAs, or ∼50% more than with monostatic observations at DSS-14. Most of the detectable asteroids were targets of opportunity that were discovered less than 15 days before the end of their observing windows. About 50% of the detectable asteroids have absolute magnitudes \\gt 25, which corresponds to diameters \\lt ∼ 30 m.

  15. Thermal History of Near-Earth Asteroids: Implications for OSIRIS-REx Asteroid Sample Return

    Science.gov (United States)

    Springmann, Alessondra; Lauretta, Dante S.

    2016-10-01

    The connection between orbital and temperature history of small Solar System bodies has only been studied through modeling. The upcoming OSIRIS-REx asteroid sample return mission provides an opportunity to connect thermal modeling predictions with laboratory studies of meteorites to predict past heating and thus dynamical histories of bodies such as OSIRIS-REx mission target asteroid (101955) Bennu. Bennu is a desirable target for asteroid sample return due to its inferred primitive nature, likely 4.5 Gyr old, with chemistry and mineralogy established in the first 10 Myr of solar system history (Lauretta et al. 2015). Delbo & Michel (2011) studied connections between the temperature and orbital history of Bennu. Their results suggest that the surface of Bennu (assuming no regolith turnover) has a 50% probability of being heated to 500 K in the past. Further, the Delbo & Michel simulations show that the temperature within the asteroid below the top layer of regolith could remain at temperatures ~100 K below that of the surface. The Touch-And-Go Sample Acquisition Mechanism on OSIRIS-REx could access both the surface and near surface regolith, collecting primitive asteroid material for study in Earth-based laboratories in 2023. To quantify the effects of thermal metamorphism on the Bennu regolith, laboratory heating experiments on carbonaceous chondrite meteorites with compositions likely similar to that of Bennu were conducted from 300-1200 K. These experiments show mobilization and volatilization of a suite of labile elements (sulfur, mercury, arsenic, tellurium, selenium, antimony, and cadmium) at temperatures that could be reached by asteroids that cross Mercury's orbit. We are able to quantify element loss with temperature for several carbonaceous chondrites and use these results to constrain past orbital histories of Bennu. When OSIRIS-REx samples arrive for analysis we will be able to measure labile element loss in the material, determine maximum past

  16. MarcoPolo-R: Near Earth Asteroid Sample Return Mission candidate as ESA-M3 class mission

    Science.gov (United States)

    Michel, Patrick; Lara, Luisa-M.; Marty, Bernard; Koschny, Detlef; Barucci, Maria Antonietta; Cheng, Andy; Bohnhardt, Hermann; Brucato, John R.; Dotto, Elisabetta; Ehrenfreund, Pascale; Franchi, Ian A.; Green, Simon F.

    2015-03-01

    MarcoPolo-R is a sample return mission to a primitive Near-Earth Asteroid (NEA) selected in February 2011 for the Assessment Study Phase at ESA in the framework of ESAfs Cosmic Vision 2 program. MarcoPolo-R is a European-led mission with a proposed NASA contribution. MarcoPolo-R takes advantage of three industrial studies completed as part of the previous Marco Polo mission (see ESA/SRE (2009)3). The aim of the new Assessment Study is to reduce the cost of the mission while maintaining its high science level, on the basis of advanced studies and technologies, as well as optimization of the mission. MarcoPolo-R will rendezvous with a unique kind of target, a primitive binary NEA, scientifically characterize it at multiple scales, and return a unique pristine sample to Earth unaltered by the atmospheric entry process or terrestrial weathering. The baseline target of MarcoPolo-R is the primitive binary NEA (175706) 1996 FG3, which offers a very efficient operational and technical mission profile. A binary target also provides enhanced science return: the choice of this target will allow new investigations to be performed more easily compared to a single object, and also enables investigations of the fascinating geology and geophysics of asteroids that are impossible to obtain from a single object. Precise measurements of the mutual orbit and rotation state of both components can be used to probe higher-level harmonics of the gravitational potential, and therefore the internal structure. A unique opportunity is offered to study the dynamical evolution driven by the YORP/Yarkovsky thermal effects. Possible migration of regolith on the primary from poles to equator allows the increasing maturity of asteroidal regolith with time to be expressed as a latitude-dependent trend, with the most-weathered material at the equator matching what is seen in the secondary. MarcoPolo-R will allow us to study the most primitive materials available to investigate early solar system

  17. Bulk Densities of Binary Asteroids from the Warm Spitzer NEO Survey

    NARCIS (Netherlands)

    Kistler, John; Trilling, D. E.; Mueller, M.; Hora, J. L.; Harris, A. W.; Bhattacharya, B.; Bottke, W. F.; Chesley, S.; Emery, J. P.; Fazo, G.; Mainzer, A.; Penprase, B.; Smith, H. A.; Spahr, T. B.; Stansberry, J. A.; Thomas, C. A.

    2010-01-01

    The Warm Spitzer NEO survey, ExploreNEOs, will observe approximately 700 Near Earth Asteroids. Several of these objects are known to be binary asteroid systems. Binary systems are interesting due to the unique opportunity they present for determining the masses and densities of their constituent bod

  18. Survey Simulations of an New Near-Earth Asteroid Detection System

    CERN Document Server

    Mainzer, A; Bauer, J; Conrow, T; Cutri, R M; Dailey, J; Fowler, J; Giorgini, J; Jarrett, T; Masiero, J; Spahr, T; Statler, T; Wright, E L

    2015-01-01

    We have carried out simulations to predict the performance of a new space-based telescopic survey operating at thermal infrared wavelengths that seeks to discover and characterize a large fraction of the potentially hazardous near-Earth asteroid (NEA) population. Two potential architectures for the survey were considered: one located at the Earth-Sun L1 Lagrange point, and one in a Venus-trailing orbit. A sample cadence was formulated and tested, allowing for the self-follow-up necessary for objects discovered in the daytime sky on Earth. Synthetic populations of NEAs with sizes >=140 m in effective spherical diameter were simulated using recent determinations of their physical and orbital properties. Estimates of the instrumental sensitivity, integration times, and slew speeds were included for both architectures assuming the properties of new large-format 10 um detector arrays capable of operating at ~35 K. Our simulation included the creation of a preliminary version of a moving object processing pipeline ...

  19. Dynamical analysis on the transitivity of Jupiter Family Comets to Near-Earth Asteroids

    Science.gov (United States)

    Erece, Orhan; Aslan, Gürkan; Eker, Zeki; Kaplan, Murat

    2016-07-01

    The purpose of this research is to identify the contribution of JFC (Jupiter Family Comet) population to NEA (Near-Earth Asteroid) region by integrating their orbits forward in time. To test and compare the statistics we also integrated NEAs having Tisserand parameters from 2 to 3 and their clones backward in time. As a result, 31.9% of orbits turned out to be Earth-crossing orbits for forward integrations while 66.7% of NEAs reached JFC region for backward integrations. From another point of view, when the number of chosen body population is considered; 304 JFC region body is possibly going to reach NEA orbits, 254 NEA region body look like come from JFC region in a comparable time interval. These results substantially support each other.

  20. Temperature-Driven Shape Changes of the Near Earth Asteroid Scout Solar Sail

    Science.gov (United States)

    Stohlman, Olive R.; Loper, Erik R.; Lockett, Tiffany E.

    2017-01-01

    Near Earth Asteroid Scout (NEA Scout) is a NASA deep space Cubesat, scheduled to launch on the Exploration Mission 1 flight of the Space Launch System. NEA Scout will use a deployable solar sail as its primary propulsion system. The sail is a square membrane supported by rigid metallic tapespring booms, and analysis predicts that these booms will experience substantial thermal warping if they are exposed to direct sunlight in the space environment. NASA has conducted sunspot chamber experiments to confirm the thermal distortion of this class of booms, demonstrating tip displacement of between 20 and 50 centimeters in a 4-meter boom. The distortion behavior of the boom is complex and demonstrates an application for advanced thermal-structural analysis. The needs of the NEA Scout project were supported by changing the solar sail design to keep the booms shaded during use of the solar sail, and an additional experiment in the sunspot chamber is presented in support of this solution.

  1. Spin Rate Diversity Amongst Ten-meter Class Near Earth Asteroids

    Science.gov (United States)

    Ryan, William; Ryan, Eileen V.

    2016-10-01

    The spin rates of small asteroids can provide insight into their mechanical structure, origin, and subsequent evolution. This is of more than just scientific interest since these are also the objects that will hit the Earth most frequently. Early statistics [Pravec and Harris, 2000] for Near Earth Asteroids (NEAs) with diameters of ~100 meters or less had resulted in the conclusion that many are rotating more rapidly than feasible for a gravitationally bound system of constituent components (i.e, 'rubble piles'). However, more recent studies [Holsapple, 2007; Scheeres et al. 2010] have focused on how non-gravitational cohesion mechanisms do not necessarily rule out a rubble pile structure for fast spin rate bodies. To further study this issue, we will report on the recent spin rate results for the smallest asteroids observed as part of our ongoing NEA target-of-opportunity characterization research [Ryan and Ryan, 2016] conducted using the Magdalena Ridge Observatory's 2.4-meter telescope.Spin rates determined by this program plus results from the current lightcurve database [Warner et al. 2016] indicate that the very smallest NEAs with H>29 rotate with periods of minutes or less. This implies that these objects possess significant strength, hinting that they are likely examples of truly monolithic fragments. However, our observations also show a great diversity in rotation periods for asteroids that are only slightly larger. In particular, the H~28.6 asteroids 2016 CC136 and 2016 CG18 were observed to rotate with periods approaching or exceeding ~2 hours, with the latter showing a tumbling behavior. In a subset of our database that includes 22 asteroids with H~27.5 (~10 meters) or greater, a full range of periods from less than a minute to greater than 2 hours (close to the minimal period of a self-gravitating system), have been identified. Moreover, at least three of these are in a tumbling state with multiple periods clearly identified, implying constraints on

  2. Solar Sailing Kinetic Energy Interceptor (KEI) Mission for Impacting/Deflecting Near-Earth Asteroids

    Science.gov (United States)

    Wie, Bong

    2005-01-01

    A solar sailing mission architecture, which requires a t least ten 160-m, 300-kg solar sail spacecraft with a characteristic acceleration of 0.5 mm/sqs, is proposed as a realistic near- term option for mitigating the threat posed by near-Earth asteroids (NEAs). Its mission feasibility is demonstrated for a fictional asteroid mitigation problem created by AIAA. This problem assumes that a 200-m asteroid, designated 2004WR, was detected on July 4, 2004, and that the expected impact will occur on January 14, 2015. The solar sailing phase of the proposed mission for the AIAA asteroid mitigation problem is comprised of the initial cruise phase from 1 AU t o 0.25 AU (1.5 years), the cranking orbit phase (3.5 years), and the retrograde orbit phase (1 year) prior to impacting the target asteroid at its perihelion (0.75 AU from the sun) on January 1, 2012. The proposed mission will require at least ten kinetic energy interceptor (KEI) solar sail spacecraft. Each KEI sailcraft consists of a 160- m, 150-kg solar sail and a 150-kg microsatellite impactor. The impactor is to be separated from a large solar sail prior to impacting the 200-m target asteroid at its perihelion. Each 150-kg microsatellite impactor, with a relative impact velocity of at least 70 km/s, will cause a conservatively estimated AV of 0.3 cm/s in the trajectory of the 200-m target asteroid, due largely to the impulsive effect of material ejected from the newly-formed crater. The deflection caused by a single impactor will increase the Earth-miss-distance by 0.45Re (where Re denotes the Earth radius of 6,378 km). Therefore, at least ten KEI sailcraft will be required for consecutive impacts, but probably without causing fragmentation, to increase the total Earth-miss-distance by 4.5Re. This miss-distance increase of 29,000 km is outside of a typical uncertainty/error of about 10,000 km in predicting the Earth-miss- distance. A conventional Delta I1 2925 launch vehicle is capable of injecting at least two KEI

  3. Characterization of Near-Earth Asteroid 2009 KC3 from Radar and Thermal Infrared Observations

    Science.gov (United States)

    Taylor, Patrick A.; Howell, E. S.; Nolan, M. C.; Benner, L. A. M.; Brozovic, M.; Giorgini, J. D.; Vervack, R. J.; Fernandez, Y. R.; Magri, C.; Mueller, M.

    2010-10-01

    We will report on the size, shape, spin state, and reflective and thermal properties of C-type, Apollo-class, potentially hazardous, near-Earth asteroid 2009 KC3 (a = 3.2 AU, e = 0.7, i = 10 deg). This object was discovered by the Siding Spring Survey in May 2009 and subsequently observed in the late summer using the Goldstone (8560 MHz, 3.5 cm) and Arecibo (2380 MHz, 12.6 cm) radar systems from August 22-29 as well as with the SpeX instrument on the NASA IRTF on August 30 and September 21. Radar images reveal a roughly spheroidal body about 1.2 km in diameter that is slightly asymmetric and elongated. Tracking of surface features and the echo bandwidth suggest a period near 12 hours, which is in agreement with a period of 11.768 hours found from lightcurve observations (P. Pravec, pers. comm.). A consistent decrease in echo bandwidth during the radar observations implies the line of sight was moving away from the equator. Radar images with resolution as fine as 7.5 m per pixel show an indentation on the leading edge (possibly a crater) and radar-bright features beyond the leading edge. The S-band circular polarization ratio of 0.25 is near the median observed among near-Earth asteroids. Thermal emission between 2 and 4 microns is essentially unchanged in SpeX observations three weeks apart despite a change in phase angle from 98 deg to 49 degrees and an increase in heliocentric distance by 0.1 AU. Furthermore, the thermal parameters derived for 2009 KC3 during a single observation do not accurately predict the thermal emission at a later time in a different viewing geometry. Determination of the shape and spin pole will help us understand how much rotation phase and illumination effects affected the thermal observations.

  4. Near Earth Asteroid Scout Solar Sail Engineering Development Unit Test Suite

    Science.gov (United States)

    Lockett, Tiffany Russell; Few, Alexander; Wilson, Richard

    2017-01-01

    The Near Earth Asteroid (NEA) Scout project is a 6U reconnaissance mission to investigate a near Earth asteroid utilizing an 86m(sub 2) solar sail as the primary propulsion system. This will be the largest solar sail NASA has launched to date. NEA Scout is currently manifested on the maiden voyage of the Space Launch System in 2018. In development of the solar sail subsystem, design challenges were identified and investigated for packaging within a 6U form factor and deployment in cis-lunar space. Analysis was able to capture understanding of thermal, stress, and dynamics of the stowed system as well as mature an integrated sail membrane model for deployed flight dynamics. Full scale system testing on the ground is the optimal way to demonstrate system robustness, repeatability, and overall performance on a compressed flight schedule. To physically test the system, the team developed a flight sized engineering development unit with design features as close to flight as possible. The test suite included ascent vent, random vibration, functional deployments, thermal vacuum, and full sail deployments. All of these tests contributed towards development of the final flight unit. This paper will address several of the design challenges and lessons learned from the NEA Scout solar sail subsystem engineering development unit. Testing on the component level all the way to the integrated subsystem level. From optical properties of the sail material to fold and spooling the single sail, the team has developed a robust deployment system for the solar sail. The team completed several deployments of the sail system in preparation for flight at half scale (4m) and full scale (6.8m): boom only, half scale sail deployment, and full scale sail deployment. This paper will also address expected and received test results from ascent vent, random vibration, and deployment tests.

  5. Capabilities of Earth-based radar facilities for near-Earth asteroid observations

    CERN Document Server

    Naidu, Shantanu P; Margot, Jean-Luc; Busch, Michael W; Taylor, Patrick A

    2016-01-01

    We evaluated the planetary radar capabilities at Arecibo, the Goldstone 70 m DSS-14 and 34-m DSS-13 antennas, the 70-m DSS-43 antenna at Canberra, the Green Bank Telescope, and the Parkes Radio Telescope in terms of their relative sensitivities and the number of known near-Earth asteroids (NEAs) detectable per year in monostatic and bistatic configurations. In the 2015 calendar year, monostatic observations with Arecibo and DSS-14 were capable of detecting 253 and 131 NEAs respectively. Combined, the two observatories were capable of detecting 276 unique NEAs. Of these, Arecibo detected 95 and Goldstone detected 39, or 38% and 30% the numbers that were possible. This indicates that a substantial number of potential targets are not being observed. The bistatic configuration with DSS-14 transmitting and the Green Bank Telescope receiving was capable of detecting about 195 NEAs, or ~50% more than with monostatic observations at DSS-14. Most of the detectable asteroids were targets-of-opportunity that were discov...

  6. Formation flying solar-sail gravity tractors in displaced orbit for towing near-Earth asteroids

    Science.gov (United States)

    Gong, Shengping; Li, Junfeng; Baoyin, Hexi

    2009-11-01

    Several methods of asteroid deflection have been proposed in literature and the gravitational tractor is a new method using gravitational coupling for near-Earth object orbit modification. One weak point of gravitational tractor is that the deflection capability is limited by the mass and propellant of the spacecraft. To enhance the deflection capability, formation flying solar sail gravitational tractor is proposed and its deflection capability is compared with that of a single solar sail gravitational tractor. The results show that the orbital deflection can be greatly increased by increasing the number of the sails. The formation flying solar sail gravitational tractor requires several sails to evolve on a small displaced orbit above the asteroid. Therefore, a proper control should be applied to guarantee that the gravitational tractor is stable and free of collisions. Two control strategies are investigated in this paper: a loose formation flying realized by a simple controller with only thrust modulation and a tight formation realized by the sliding-mode controller and equilibrium shaping method. The merits of the loose and tight formations are the simplicity and robustness of their controllers, respectively.

  7. Radar imaging, shape modeling, and Yarkovsky drift of near-Earth asteroid 1566 Icarus

    Science.gov (United States)

    Greenberg, Adam; Margot, Jean-Luc; Verma, Ashok Kumar; Taylor, Patrick A.

    2016-10-01

    Near-Earth asteroid (NEA) 1566 Icarus ( a=1.08 au, e=0.83, i=22.8 degrees) made a rare close approach to Earth in June 2015 at 22 lunar distances (LD). Its detection during the 1968 approach (16 LD) was the first in the history of asteroid radar astronomy. The next approach in 1996 (40 LD) did not yield radar images. We provide the results of analyses of the first radar images obtained of 1566 Icarus during the 2015 close approach. These data suggest that this object is 1.77+-0.3 km in diameter, which is larger than previously thought, and has strongly specular surface scattering behavior. We also provide constraints on 1566 Icarus' spin pole orientation. Finally, we present the first use of our Integration and Determination of Orbits System (IDOS) for the generation of radar predictions, and we demonstrate its ability to measure subtle perturbations on NEA orbits by measuring 1566 Icarus' orbit-averaged drift in semi-major axis (-5.8+-0.5 x 10^-4 AU/Myr).

  8. Migration of Jupiter-family comets and resonant asteroids to near-Earth space

    CERN Document Server

    Ipatov, S I

    2003-01-01

    We estimated the rate of comet and asteroid collisions with the terrestrial planets by calculating the orbits of 13000 Jupiter-crossing objects (JCOs) and 1300 resonant asteroids and computing the probabilities of collisions based on random-phase approximations and the orbital elements sampled with a 500 yr step. The Bulirsh-Stoer and a symplectic orbit integrator gave similar results for orbital evolution, but sometimes give different collision probabilities with the Sun. A small fraction of former JCOs reached orbits with aphelia inside Jupiter's orbit, and some reached Apollo orbits with semi-major axes less than 2 AU, Aten orbits, and inner-Earth orbits (with aphelia less than 0.983 AU) and remained there for millions of years. Though less than 0.1% of the total, these objects were responsible for most of the collision probability of former JCOs with Earth and Venus. Some Jupiter-family comets can reach inclinations i>90 deg. We conclude that a significant fraction of near-Earth objects could be extinct c...

  9. SURVEY SIMULATIONS OF A NEW NEAR-EARTH ASTEROID DETECTION SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Mainzer, A.; Bauer, J.; Giorgini, J.; Masiero, J. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Grav, T. [Planetary Science Institute, Tucson, AZ (United States); Conrow, T.; Cutri, R. M.; Dailey, J.; Fowler, J.; Jarrett, T. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Spahr, T. [Minor Planet Center, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street MS-18, Cambridge, MA 02138 (United States); Statler, T. [Astrophysical Institute, Ohio University (United States); Wright, E. L. [Department of Astronomy and Astrophysics, University of California Los Angeles, Los Angeles, CA (United States)

    2015-05-15

    We have carried out simulations to predict the performance of a new space-based telescopic survey operating at thermal infrared wavelengths that seeks to discover and characterize a large fraction of the potentially hazardous near-Earth asteroid (NEA) population. Two potential architectures for the survey were considered: one located at the Earth–Sun L1 Lagrange point, and one in a Venus-trailing orbit. A sample cadence was formulated and tested, allowing for the self-follow-up necessary for objects discovered in the daytime sky on Earth. Synthetic populations of NEAs with sizes as small as 140 m in effective spherical diameter were simulated using recent determinations of their physical and orbital properties. Estimates of the instrumental sensitivity, integration times, and slew speeds were included for both architectures assuming the properties of newly developed large-format 10 μm HgCdTe detector arrays capable of operating at ∼35 K. Our simulation included the creation of a preliminary version of a moving object processing pipeline suitable for operating on the trial cadence. We tested this pipeline on a simulated sky populated with astrophysical sources such as stars and galaxies extrapolated from Spitzer Space Telescope and Wide-field Infrared Explorer data, the catalog of known minor planets (including Main Belt asteroids, comets, Jovian Trojans, planets, etc.), and the synthetic NEA model. Trial orbits were computed for simulated position-time pairs extracted from the synthetic surveys to verify that the tested cadence would result in orbits suitable for recovering objects at a later time. Our results indicate that the Earth–Sun L1 and Venus-trailing surveys achieve similar levels of integral completeness for potentially hazardous asteroids larger than 140 m; placing the telescope in an interior orbit does not yield an improvement in discovery rates. This work serves as a necessary first step for the detailed planning of a next-generation NEA survey.

  10. Solar Radiation and Near-Earth Asteroids: Thermophysical Modeling and New Measurements of the Yarkovsky Effect

    Science.gov (United States)

    Nugent, Carolyn Rosemary

    This dissertation examines the influence of solar radiation on near-Earth asteroids (NEAs); it investigates thermal properties and examines changes to orbits caused by the process of anisotropic re-radiation of sunlight called the Yarkovsky effect. For the first portion of this dissertation, we used geometric albedos pV and diameters derived from the Wide-Field Infrared Survey Explorer (WISE), as well as geometric albedos and diameters from the literature, to produce more accurate diurnal Yarkovsky drift predictions for 540 NEAs out of the current sample of ˜8800 known objects. These predictions are intended to assist observers, and should enable future Yarkovsky detections. The second portion of this dissertation introduces a new method for detecting the Yarkovsky drift. We identified and quantified semi-major axis drifts in NEAs by performing orbital fits to optical and radar astrometry of all numbered NEAs. We discuss a subset of 54 NEAs that exhibit some of the most reliable and strongest drift rates. Our selection criteria include a Yarkovsky sensitivity metric that quantifies the detectability of semi-major axis drift in any given data set, a signal-to-noise metric, and orbital coverage requirements. In 42 cases, the observed drifts (˜ 10-3 AU/Myr) agree well with numerical estimates of Yarkovsky drifts. This agreement suggests that the Yarkovsky effect is the dominant non-gravitational process affecting these orbits, and allows us to derive constraints on asteroid physical properties. We define the Yarkovsky efficiency fY as the ratio of the change in orbital energy to incident solar radiation energy, and we find that typical Yarkovsky efficiencies are ˜10-5. The final portion of this dissertation describes the development of and results from a detailed thermal model of potentially hazardous asteroid (29075) 1950 DA. This model combines radar-derived shape models of the object and fourteen 12 micron observations by the WISE spacecraft. The observations

  11. Thermal inertia as an indicator of rockiness variegation on near-Earth asteroid surfaces

    Science.gov (United States)

    Ali-Lagoa, Victor; Delbo, Marco; Hanus, Josef

    2016-10-01

    Determining key physical properties of asteroids such as sizes and albedos or reflectance spectra is crucial to understand their origins and the processes that they have undergone during their evolution. In particular, one of the aims of NEOShield-2 project, funded by the European Union's Horizon 2020 Research and Innovation programme, is to physically characterize small near Earth asteroids (NEA) in an effort to determine effective mitigation strategies in case of impact with our planet [Harris et al. 2013 2013AcAau,90,80H].We performed thermophysical modelling of NEAs, such as (1685) Toro, and potentially hazardous asteroids (PHAs), such as (33342) 1998 WT24. In addition to size, thermophysical models (TPM) of asteroids can constrain the surface thermal inertia, which is related to the material composition and physical nature, namely its "rockiness" or typical size of the particles on its surface. These have observable effects on the surface temperature distribution as a function of time and thus on the thermal infrared fluxes we observe, to which we can fit our model.In the case of WT24, its thermal inertia has been previously constrained to be in the range 100-300 SI units [Harris et al. 2007, Icarus 188, 414H]. But this was based on a spherical shape model approximation since no shape model was available by the time. Such a low thermal inertia value seems in disagreement with a relatively high metal content of the enstatite chondrites, the meteorite type to which WT24, classified as an E-type [Lazzarin et al. 2004 A&A 425L, 25L], has been spectrally associated. Using a three-dimensional model and spin vector based on radar observations [Busch et al. 2008 Icarus 197, 375B], our TPM produces a higher best-fitting value of the thermal inertia. We also find the intriguing possibility that the hemisphere of WT24 dominated by concave terrains, possibly be the result of an impact crater, has a higher thermal inertia. This would be similar to the case of our Moon

  12. Determination of Eros Physical Parameters for Near Earth Asteroid Rendezvous Orbit Phase Navigation

    Science.gov (United States)

    Miller, J. K.; Antreasian, P. J.; Georgini, J.; Owen, W. M.; Williams, B. G.; Yeomans, D. K.

    1995-01-01

    Navigation of the orbit phase of the Near Earth steroid Rendezvous (NEAR) mission will re,quire determination of certain physical parameters describing the size, shape, gravity field, attitude and inertial properties of Eros. Prior to launch, little was known about Eros except for its orbit which could be determined with high precision from ground based telescope observations. Radar bounce and light curve data provided a rough estimate of Eros shape and a fairly good estimate of the pole, prime meridian and spin rate. However, the determination of the NEAR spacecraft orbit requires a high precision model of Eros's physical parameters and the ground based data provides only marginal a priori information. Eros is the principal source of perturbations of the spacecraft's trajectory and the principal source of data for determining the orbit. The initial orbit determination strategy is therefore concerned with developing a precise model of Eros. The original plan for Eros orbital operations was to execute a series of rendezvous burns beginning on December 20,1998 and insert into a close Eros orbit in January 1999. As a result of an unplanned termination of the rendezvous burn on December 20, 1998, the NEAR spacecraft continued on its high velocity approach trajectory and passed within 3900 km of Eros on December 23, 1998. The planned rendezvous burn was delayed until January 3, 1999 which resulted in the spacecraft being placed on a trajectory that slowly returns to Eros with a subsequent delay of close Eros orbital operations until February 2001. The flyby of Eros provided a brief glimpse and allowed for a crude estimate of the pole, prime meridian and mass of Eros. More importantly for navigation, orbit determination software was executed in the landmark tracking mode to determine the spacecraft orbit and a preliminary shape and landmark data base has been obtained. The flyby also provided an opportunity to test orbit determination operational procedures that will be

  13. Astrometry of Near-Earth Asteroids Using Remotely-Operated Robotic Telescopes

    Science.gov (United States)

    Holvorcem, P. R.; Schwartz, M.; Juels, C. W.; Breganhola, M.; Camargo, J.; Teixeira, R.; Fidêncio Neto, M.

    2003-11-01

    A Near-Earth object (NEO) astrometric follow-up program was started at Barão Geraldo (Campinas, SP, Brazil) in 1996 and transferred to Observatório Abrahão de Moraes (Valinhos, SP) in early 1998. Since mid-1999, this program uses a 36-cm telescope on a robotic mount, which is remotely operated from Barão Geraldo through an internet connection. The planning of observation sessions is made with the help of especially developed software which automatically allocates telescope time to the targets which one wishes to observe on a given night, taking into account several observational constraints and the physical characteristics of the telescope and robotic mount. The output of the time allocation program is a set of scripts containing commands for the telescope and CCD camera, and topocentric ephemeris for the various solar-system targets (whose computation includes full planetary perturbations). These scripts are uploaded to the telescope control computer, and executed autonomously by the telescope. The resulting images are downloadedin near-real time and analyzed with the help of automated astrometry and asteroid detection programs. Since its beginning, this program has produced 1100 astrometric observations of NEOs, a few hundred observations of comets, and the discovery of 27 main belt minor planets, 19 of which now have permanent numbers. The same methodology of remote operation has been applied since mid-1999 to carry out NEO follow-up campaigns and asteroid searches with a 36-cm telescope at Tenagra I Observatory (near Cottage Grove, OR, USA), with 36-, 50-, and 81-cm telescopes at Tenagra II Observatory (near Patagonia, AZ, USA), and with 12-, 32-, 37-, and 50-cm telescope at Fountain Hills (AZ). These campaigns have produced more than 2000 observations of NEOs, a few hundred observations of comets, and the discovery of about 210 minor planets.

  14. Solar Sail Attitude Control System for the NASA Near Earth Asteroid Scout Mission

    Science.gov (United States)

    Orphee, Juan; Diedrich, Ben; Stiltner, Brandon; Becker, Chris; Heaton, Andrew

    2017-01-01

    An Attitude Control System (ACS) has been developed for the NASA Near Earth Asteroid (NEA) Scout mission. The NEA Scout spacecraft is a 6U cubesat with an eighty-six square meter solar sail for primary propulsion that will launch as a secondary payload on the Space Launch System (SLS) Exploration Mission 1 (EM-1) and rendezvous with a target asteroid after a two year journey, and will conduct science imagery. The spacecraft ACS consists of three major actuating subsystems: a Reaction Wheel (RW) control system, a Reaction Control System (RCS), and an Active Mass Translator (AMT) system. The reaction wheels allow fine pointing and higher rates with low mass actuators to meet the science, communication, and trajectory guidance requirements. The Momentum Management System (MMS) keeps the speed of the wheels within their operating margins using a combination of solar torque and the RCS. The AMT is used to adjust the sign and magnitude of the solar torque to manage pitch and yaw momentum. The RCS is used for initial de-tumble, performing a Trajectory Correction Maneuver (TCM), and performing momentum management about the roll axis. The NEA Scout ACS is able to meet all mission requirements including attitude hold, slews, pointing for optical navigation and pointing for science with margin and including flexible body effects. Here we discuss the challenges and solutions of meeting NEA Scout mission requirements for the ACS design, and present a novel implementation of managing the spacecraft Center of Mass (CM) to trim the solar sail disturbance torque. The ACS we have developed has an applicability to a range of potential missions and does so in a much smaller volume than is traditional for deep space missions beyond Earth.

  15. Orbital, spin state and thermophysical characterization of near-Earth asteroid (3200) Phaethon

    CERN Document Server

    Hanus, J; Vokrouhlicky, D; Pravec, P; Emery, J P; Ali-Lagoa, V; Bolin, B; Devogele, M; Dyvig, R; Galad, A; Jedicke, R; Kornos, L; Kusnirak, P; Licandro, J; Reddy, V; Rivet, J-P; Vilagi, J; Warner, B D

    2016-01-01

    The near-Earth asteroid (3200) Phaethon is an intriguing object: its perihelion is only at 0.14 au and is associated with the Geminid meteor stream. We aim to use all available disk-integrated optical data to derive reliable convex shape model of Phaethon. By interpreting the available space- and ground-based thermal infrared data and Spitzer spectra using a thermophysical model, we also aim to further constrain its size, thermal inertia, and visible geometric albedo. We apply the convex inversion method to the new optical data obtained by six instruments together with the already existing observations. The convex shape model is then used as an input for the thermophysical modeling. We also study the long-term stability of Phaethon's orbit and spin axis by a numerical orbital and rotation-state integrator. We present a new convex shape model and rotational state of Phaethon - sidereal rotation period of 3.603958(2) h and ecliptic coordinates of the preferred pole orientation of (319$^{\\circ}$, $-$39$^{\\circ}$...

  16. The IMPACTON Project: Pole and Shape of Seven near-Earth Asteroids

    Science.gov (United States)

    Lazzaro, Daniela; Silva, José Sergio; Rodrigues, Teresinha; Márcio Carvano, Jorge; Roig, Fernando; Souza, Roberto Pereira e.; IMPACTON Team

    2015-08-01

    The formation and evolution of Solar System small bodies, in particular those in near-Earth orbits, is a complex problem which solution strongly depends on a better knowledge of their physical properties. To contribute to the international efforts in this direction the IMPACTON project (www.on.br/IMPACTON) set up a dedicated facility in a remote region in the northeast part of Brazil, denominated Observatório Astronômico do Sertão de Itaparica (OASI - code Y28, Itacuruba).Using the 1-m telescope of the OASI we observed more of 40 NEAs during several observational runs between March 2012 and October 2014. Our observations were made using an Apogee Alta U47 CCD camera, 1024 X 1024 pixels, giving a 5.9 x 5.9 arcmin field, and using an R Johnson filter.Standard reduction procedures were applied and relative magnitudes were used to obtain lightcurves for the observed asteroids. The application of the inversion of method developed by Kaasalainen and Torppa (2001) and Kaasalainen et al. (2001) allowed us to derive the rotational period for 14 NEAs and, for 7 of these, also the pole direction and the shape. The implications of the obtained results will be discussed.

  17. A resonant family of dynamically cold small bodies in the near-Earth asteroid belt

    CERN Document Server

    Marcos, C de la Fuente

    2013-01-01

    Near-Earth objects (NEOs) moving in resonant, Earth-like orbits are potentially important. On the positive side, they are the ideal targets for robotic and human low-cost sample return missions and a much cheaper alternative to using the Moon as an astronomical observatory. On the negative side and even if small in size (2-50 m), they have an enhanced probability of colliding with the Earth causing local but still significant property damage and loss of life. Here we show that the recently discovered asteroid 2013 BS45 is an Earth co-orbital, the sixth horseshoe librator to our planet. In contrast with other Earth's co-orbitals, its orbit is strikingly similar to that of the Earth yet at an absolute magnitude of 25.8, an artificial origin seems implausible. The study of the dynamics of 2013 BS45 coupled with the analysis of NEO data show that it is one of the largest and most stable members of a previously undiscussed dynamically cold group of small NEOs experiencing repeated trappings in the 1:1 commensurabi...

  18. Design of Round-trip Trajectories to Near-Earth Asteroids Utilizing a Lunar Flyby

    Science.gov (United States)

    Hernandez, Sonia; Barbee, Brent W.

    2011-01-01

    There are currently over 7,700 known Near-Earth Asteroids (NEAs), and more are being discovered on a continual basis. Current models predict that the actual order of magnitude of the NEA population may range from 10' to 10 6 . The close proximity of NEA orbits to Earth's orbit makes it possible to design short duration round-trip trajectories to NEAs under the proper conditions. In previous work, 59 potentially accessible NEAs were identified for missions that depart Earth between the years 2016 and 2050 and have round-trip flight times of a year or less. We now present a new method for designing round-trip trajectories to NEAs in which the Moon's gravity aids the outbound trajectory via a lunar flyby. In some cases this gravity assist can reduce the overall spacecraft propellant required for the mission, which in turn can allow NEAs to be reached which would otherwise be inaccessible to a given mission architecture. Results are presented for a specific case study on NEA 2003 LN6.

  19. Human Expeditions to Near-Earth Asteroids: Implications for Exploration, Resource Utilization, Science, and Planetary Defense

    Science.gov (United States)

    Abell, Paul; Mazanek, Dan; Barbee, Brent; Landis, Rob; Johnson, Lindley; Yeomans, Don; Friedensen, Victoria

    2013-01-01

    Over the past several years, much attention has been focused on human exploration of near-Earth asteroids (NEAs) and planetary defence. Two independent NASA studies examined the feasibility of sending piloted missions to NEAs, and in 2009, the Augustine Commission identified NEAs as high profile destinations for human exploration missions beyond the Earth-Moon system as part of the Flexible Path. More recently the current U.S. presidential administration directed NASA to include NEAs as destinations for future human exploration with the goal of sending astronauts to a NEA in the mid to late 2020s. This directive became part of the official National Space Policy of the United States of America as of June 28, 2010. With respect to planetary defence, in 2005 the U.S. Congress directed NASA to implement a survey program to detect, track, and characterize NEAs equal or greater than 140 m in diameter in order to access the threat from such objects to the Earth. The current goal of this survey is to achieve 90% completion of objects equal or greater than 140 m in diameter by 2020.

  20. Data mining of near-Earth asteroids in the Subaru Suprime-Cam archive

    Science.gov (United States)

    Vaduvescu, O.; Conovici, M.; Popescu, M.; Sonka, A.; Paraschiv, A.; Lacatus, D.; Tudorica, A.; Hudin, L.; Curelaru, L.; Inceu, V.; Zavoianu, D.; Cornea, R.; Toma, R.; Asher, D. J.; Hadnett, J.; Cheallaigh, L. Ó.

    2017-06-01

    As part of the EURONEAR project, almost 70,000 mosaic Suprime-Cam images taken between 1999 and 2013 were data mined for about 9,800 near Earth asteroids (NEAs) known by 2013 May. Using our PRECOVERY server and the "Find Subaru CCD" tool, we scrutinized 4,186 candidate CCD images possibly holding 518 NEAs. We found 113 NEAs as faint as V<25 magnitude, their positions being measured in 589 images using Astrometrica, then reported to the Minor Planet Center. Among them, 18 objects represent encounters of previously single opposition NEAs, their orbital arcs being extended by up to 10 years. In the second part of this work we searched for unknown NEAs in 78 sequences (780 CCD fields) of 4-5 mosaic images selected from the same Suprime-Cam archive and totaling 16.6 sq.deg, with the aim to assess the faint NEA distribution observable with an 8-m class survey. A total of 2,018 moving objects were measured, from which we identified 18 better NEA candidates. Using the R_c filter in good weather conditions, mostly dark time and sky directions slightly biased towards the ecliptic, at least one NEA could be discovered in every 1 sq.deg surveyed.

  1. Optimal design of near-Earth asteroid sample-return trajectories in the Sun-Earth-Moon system

    Science.gov (United States)

    He, Shengmao; Zhu, Zhengfan; Peng, Chao; Ma, Jian; Zhu, Xiaolong; Gao, Yang

    2016-08-01

    In the 6th edition of the Chinese Space Trajectory Design Competition held in 2014, a near-Earth asteroid sample-return trajectory design problem was released, in which the motion of the spacecraft is modeled in multi-body dynamics, considering the gravitational forces of the Sun, Earth, and Moon. It is proposed that an electric-propulsion spacecraft initially parking in a circular 200-km-altitude low Earth orbit is expected to rendezvous with an asteroid and carry as much sample as possible back to the Earth in a 10-year time frame. The team from the Technology and Engineering Center for Space Utilization, Chinese Academy of Sciences has reported a solution with an asteroid sample mass of 328 tons, which is ranked first in the competition. In this article, we will present our design and optimization methods, primarily including overall analysis, target selection, escape from and capture by the Earth-Moon system, and optimization of impulsive and low-thrust trajectories that are modeled in multi-body dynamics. The orbital resonance concept and lunar gravity assists are considered key techniques employed for trajectory design. The reported solution, preliminarily revealing the feasibility of returning a hundreds-of-tons asteroid or asteroid sample, envisions future space missions relating to near-Earth asteroid exploration.

  2. Optimal design of near-Earth asteroid sample-return trajectories in the Sun-Earth-Moon system

    Institute of Scientific and Technical Information of China (English)

    Shengmao He; Zhengfan Zhu; Chao Peng; Jian Ma; Xiaolong Zhu; Yang Gao

    2016-01-01

    In the 6th edition of the Chinese Space Trajec-tory Design Competition held in 2014, a near-Earth asteroid sample-return trajectory design problem was released, in which the motion of the spacecraft is modeled in multi-body dynamics, considering the gravitational forces of the Sun, Earth, and Moon. It is proposed that an electric-propulsion spacecraft initially parking in a circular 200-km-altitude low Earth orbit is expected to rendezvous with an asteroid and carry as much sample as possible back to the Earth in a 10-year time frame. The team from the Technology and Engi-neering Center for Space Utilization, Chinese Academy of Sciences has reported a solution with an asteroid sample mass of 328 tons, which is ranked first in the competition. In this article, we will present our design and optimization methods, primarily including overall analysis, target selec-tion, escape from and capture by the Earth–Moon system, and optimization of impulsive and low-thrust trajectories that are modeled in multi-body dynamics. The orbital res-onance concept and lunar gravity assists are considered key techniques employed for trajectory design. The reported solution, preliminarily revealing the feasibility of returning a hundreds-of-tons asteroid or asteroid sample, envisions future space missions relating to near-Earth asteroid explo-ration.

  3. The Shape of Near-Earth Asteroid 275677 (2000 RS11) From Inversion of Arecibo and Goldstone Radar Images

    Science.gov (United States)

    Brauer, Kaley; Busch, Michael W.; Benner, Lance A. M.; Brozovic, Marina; Howell, Ellen S.; Nolan, Michael C.; Springmann, Alessondra; Giorgini, Jon D.; Taylor, Patrick A.; Jao, Joseph S.

    2015-11-01

    We observed near-Earth asteroid 2000 RS11 with the Arecibo and Goldstone planetary radars during a 0.035 au approach in March 2014, obtaining delay-Doppler images between March 13 and March 17. The finest-resolution images have range resolution of 7.5 m/pixel and show that RS11 is a contact binary with complex topography. We used the SHAPE software package (Magri et al., Icarus 186, 156-160 2007) to create a physical model of RS11 and its spin state from these delay-Doppler images.The rotation period of RS11 is well constrained from optical lightcurves, P = 4.444 ± 0.001 h (Warner et al., Minor Planet Bulletin 41, 160; 2014 and Benishek, Minor Planet Bulletin 41, 257; 2014). We found two possible pole directions and corresponding shape models, mirror images of one another, which provide equally good fits to the radar data. RS11’s pole direction is either (λ , β) = (155°, 30°) ± 10° or (335°, -30°) ± 10° in J2000 ecliptic coordinates. The most likely pole directions of RS11 are not aligned with the heliocentric orbit normal and instead have an obliquity within 10° of 56° or 124°.Our best-fit shape models are 1400-vertex polyhedra comprising two lobes in contact. The lengths of RS11’s principal axes are 698 ± 71 m, 578 ± 59 m, and 758 ± 77 m. RS11 has a volume of 0.086 ± 0.026 km^3. The long axis of RS11’s larger lobe is 751 ± 77 m and the long axis of the smaller lobe is 398 ± 41 m; the volume ratio between these lobes is roughly 2.7 ± 10%. Spectral data informs us that RS11 is an S-class object (Lazzarin et al., Icarus 169, 379; 2004).RS11's shape is unusual compared with those of other contact binary NEAs imaged by radar. Its larger lobe is flattened. Additionally, while the neck between the smaller and larger lobes of most contact binaries is located near the larger lobe's longest principal axis (such as in the cases of 25143 Itokawa and 4179 Toutatis), RS11's neck is near its larger lobe's shortest principal axis. RS11 is the first

  4. Mining the ESO WFI and INT WFC archives for known Near Earth Asteroids. Mega-Precovery software

    CERN Document Server

    Vaduvescu, O; Comsa, I; Paraschiv, A; Lacatus, D; Sonka, A; Tudorica, A; Birlan, M; Suciu, O; Char, F; Constantinescu, M; Badescu, T; Badea, M; Vidican, D; Opriseanu, C

    2013-01-01

    The ESO/MPG WFI and the INT WFC wide field archives comprising 330,000 images were mined to search for serendipitous encounters of known Near Earth Asteroids (NEAs) and Potentially Hazardous Asteroids (PHAs). A total of 152 asteroids (44 PHAs and 108 other NEAs) were identified using the PRECOVERY software, their astrometry being measured on 761 images and sent to the Minor Planet Centre. Both recoveries and precoveries were reported, including prolonged orbital arcs for 18 precovered objects and 10 recoveries. We analyze all new opposition data by comparing the orbits fitted before and after including our contributions. We conclude the paper presenting Mega-Precovery, a new online service focused on data mining of many instrument archives simultaneously for one or a few given asteroids. A total of 28 instrument archives have been made available for mining using this tool, adding together about 2.5 million images forming the Mega-Archive.

  5. Data Processing for the Near Earth Asteroid Rendezvous (NEAR), X-Ray and Gamma-Ray Spectrometer (XRS) Ground System

    Science.gov (United States)

    McClanahan, Timothy P.; Mikheeva, I.; Trombka, J. I.; Floyd, S. R.; Boynton, W. V.; Bailey, H.; Bhangoo, J.; Starr, R.; Clark, P. E.; Evans, L. G.

    1999-01-01

    An X-ray and Gamma-ray spectrometer (XGRS) is onboard the Near Earth Asteroid Rendezvous (NEAR) spacecraft to determine the elemental composition of the surface of the asteroid 433Eros. The Eros asteroid is highly non-spherical in physical shape and the development of data management and analysis methodologies are in several areas a divergence from traditional remotely sensed geographical information systems techniques. Field of view and asteroid surface geometry must be derived virtually and then combined with real measurements of solar, spectral and instrument calibration information to derive meaningful scientific results. Spatial resolution of planned geochemical maps will be improved from the initial conditions of low statistical significance per integration by repeated surface flyovers and regional spectral accumulation. This paper describes the results of a collaborative effort of design and development of the NEAR XGRS instrument ground system undertaken by participants at the Goddard Space Flight Center, University of Arizona, Cornell University, Applied Physics Laboratory, and Max Plank institute.

  6. Data Processing for the Near Earth Asteroid Rendezvous (NEAR), X-ray and Gamma-ray Spectrometer (XGRS) Ground System

    Science.gov (United States)

    McClanahan, Timothy P.; Mikheeva, I.; Trombka, J. I.; Floyd, S. R.; Boynton, W. V.; Bailey, H.; Bhangoo, J.; Starr, R.; Clark, P. E.; Evans, L. G.

    1999-01-01

    An X-ray and Gamma-ray spectrometer (XGRS) is onboard the Near Earth Asteroid Rendezvous (NEAR) spacecraft to determine the elemental composition of the surface of the asteroid 433Eros. The Eros asteroid is highly non-spherical in physical shape and the development of data management and analysis methodologies are in several areas a divergence from traditional remotely sensed geographical information systems techniques. Field of view and asteroid surface geometry must be derived virtually and then combined with real measurements of solar, spectral and instrument calibration information to derive meaningful scientific results. Spatial resolution of planned geochemical maps will be improved from the initial conditions of low statistical significance per integration by repeated surface flyovers and regional spectral accumulation. This paper describes the results of a collaborative effort of design and development of the NEAR XGRS instrument ground system undertaken by participants at the Goddard Space Flight Center, University of Arizona, Cornell University, Applied Physics Laboratory, and Max Plank institute.

  7. Near Earth asteroids associated with the Sigma-Capricornids meteoroid stream

    Science.gov (United States)

    Gulchekhra, Kokhirova; Pulat, Babadzhanov; Umed, Khamroev

    The Near Earth Asteroids (NEAs) 2008BO16, 2011EC41, and 2013CT36 (http://newton.dm.\\unipi.it/neodys, 2013) have very similar orbits according to the D_{SH} criterion of Southworth, Hawkins (1963). Additionally, their orbits are classed as comet-like by the Tisserand invariant values (Kresak 1982; Kosai 1992). The orbital evolution investigation shows, that during one cycle of variations of the argument of perihelion omega, the asteroids cross the Earth’s orbit four times. Consequently, a developed meteoroid stream, possible associated with them, might produce four meteor showers (Babadzhanov, Obrubov 1992). Theoretical parameters of the predicted showers were calculated and identified with the observable nighttime sigma-Capricornids (Sekanina 1973; Jenniskens 2006) and chi-Sagittarids (Sekanina 1976), and daytime chi-Capricornids (Sekanina 1976) and Capricornids-Sagittarids (Sekanina 1973) meteor showers. The similar and comet-like orbits and association with the meteoroid stream producing four active showers are strong indications that these asteroids have a common cometary origin. Earlier the NEAs (2101) Adonis and 1995CS, which additionally is potentially hazardous asteroid (PHA), were recognized as dormant comets because of their link with the same meteoroid stream (Babadzhanov 2003). So, a conclusion was made, that either the considered NEAs are large sized splinters of the Adonis, or all five objects are fragments of a larger comet that was the parent body of the sigma-Capricornids meteoroid stream, and whose break-up occurred several tens of thousands years ago. During 2010-2011 years three fireballs were photographed by the Tajikistan fireball network (Babadzhanov, Kokhirova 2009), belonging to the sigma-Capricornids meteor shower. Taking into account the observations else six fireballs of this shower in the Canada and USA (Halliday et al. 1996; McCrosky et al. 1978), the mean radiant coordinates, the period of activity, as well as the mean daily radiant

  8. Shape, size, physical properties and nature of low-perihelion near-Earth asteroid (3200) Phaethon

    Science.gov (United States)

    Hanus, Josef; Delbo, Marco; Vokrouhlicky, David; Pravec, Petr; Emery, Joshua P.; Ali-Lagoa, Victor; Bolin, Bryce T.; Devogele, Maxime; Dyvig, Ron; Galad, Adrian; Jedicke, Robert; Kornos, Leos; Kusnirak, Peter; Licandro, Javier; Reddy, Vishnu; Warner, Brian D.; Rivet, Jean-Pierre; Vilagi, Jozef

    2016-10-01

    We apply the convex inversion method to the new optical data obtained by six instruments together with the already existing observations and derive convex shape model of low-perihelion near-Earth asteroid (3200) Phaethon. This shape model is then used as an input for the thermophysical modeling. We present new convex shape model and rotational state of Phaethon - sidereal rotation period of 3.603958(2) h and ecliptic coordinates of the preferred pole orientation of (319, -39) with a 5 degree uncertainty. Moreover, we derive its size (D=5.1±0.2 km), thermal inertia (Γ=600±200 J m-2s-1/2K-1), geometric visible albedo (pV=0.122±0.008), and estimate the macroscopic surface roughness by the thermophysical model. We also estimate the average size of the surface regolith to few centimeters. The Spitzer emission spectrum of Phaethon is similar to those of CV/CK carbonaceous chondrite meteorites, match with CI/CM carbonaceous chondrites is ruled out. We also study the long-term stability of Phaethon's orbit and spin axis by a numerical orbital and rotation-state integrator. We find that the Sun illumination at the perihelion passage during past thousands of years is not connected to a specific area on the surface implying non-preferential heating. Considering the most important meteor stream of the Geminids is associated with Phaethon, we predict that the meteorites dropped by Geminids are CVs or CKs. We also discuss the possible dynamical link between Phaethon and Pallas and its collisional family.

  9. Near-Earth asteroid (3200) Phaethon: Characterization of its orbit, spin state, and thermophysical parameters

    Science.gov (United States)

    Hanuš, J.; Delbo', M.; Vokrouhlický, D.; Pravec, P.; Emery, J. P.; Alí-Lagoa, V.; Bolin, B.; Devogèle, M.; Dyvig, R.; Galád, A.; Jedicke, R.; Kornoš, L.; Kušnirák, P.; Licandro, J.; Reddy, V.; Rivet, J.-P.; Világi, J.; Warner, B. D.

    2016-07-01

    Context. The near-Earth asteroid (3200) Phaethon is an intriguing object: its perihelion is at only 0.14 au and is associated with the Geminid meteor stream. Aims: We aim to use all available disk-integrated optical data to derive a reliable convex shape model of Phaethon. By interpreting the available space- and ground-based thermal infrared data and Spitzer spectra using a thermophysical model, we also aim to further constrain its size, thermal inertia, and visible geometric albedo. Methods: We applied the convex inversion method to the new optical data obtained by six instruments and to previous observations. The convex shape model was then used as input for the thermophysical modeling. We also studied the long-term stability of Phaethon's orbit and spin axis with a numerical orbital and rotation-state integrator. Results: We present a new convex shape model and rotational state of Phaethon: a sidereal rotation period of 3.603958(2) h and ecliptic coordinates of the preferred pole orientation of (319°, -39°) with a 5° uncertainty. Moreover, we derive its size (D = 5.1 ± 0.2 km), thermal inertia (Γ = 600 ± 200 J m-2 s-1/2 K-1), geometric visible albedo (pV = 0.122 ± 0.008), and estimate the macroscopic surface roughness. We also find that the Sun illumination at the perihelion passage during the past several thousand years is not connected to a specific area on the surface, which implies non-preferential heating.

  10. Human Health and Performance Considerations for Exploration of Near-Earth Asteroids

    Science.gov (United States)

    Kundrot, Craig; Steinberg, Susan; Charles, John

    2010-01-01

    This presentation will describe the human health and performance issues that are anticipated for the human exploration of near-Earth asteroids (NEA). Humans are considered a system in the design of any such deep-space exploration mission, and exploration of NEA presents unique challenges for the human system. Key factors that define the mission are those that are strongly affected by distance and duration. The most critical of these is deep-space radiation exposure without even the temporary shielding of a nearby large planetary body. The current space radiation permissible exposure limits (PEL) restrict mission duration to 3-10 months depending on age and gender of crewmembers and stage of the solar cycle. Factors that affect mission architecture include medical capability; countermeasures for bone, muscle, and cardiovascular atrophy during continuous weightlessness; restricted food supplies; and limited habitable volume. The design of a habitat that can maintain the physical and psychological health of the crew and support mission operations with limited intervention from Earth will require an integrated research and development effort by NASA s Human Research Program, engineering, and human factors groups. Limited abort and return options for an NEA mission are anticipated to have important effects on crew psychology as well as influence medical supplies and training requirements of the crew. Other important factors are those related to isolation, confinement, communication delays, autonomous operations, task design, small crew size, and even the unchanging view outside the windows for most of the mission. Geological properties of the NEA will influence design of sample handling and containment, and extravehicular activity capabilities including suit ports and tools. A robotic precursor mission that collects basic information on NEA surface properties would reduce uncertainty about these aspects of the mission as well as aid in design of mission architecture and

  11. Application of recursive approaches to differential orbit correction of near Earth asteroids

    Science.gov (United States)

    Dmitriev, Vasily; Lupovka, Valery; Gritsevich, Maria

    2016-10-01

    Comparison of three approaches to the differential orbit correction of celestial bodies was performed: batch least squares fitting, Kalman filter, and recursive least squares filter. The first two techniques are well known and widely used (Montenbruck, O. & Gill, E., 2000). The most attention is paid to the algorithm and details of program realization of recursive least squares filter. The filter's algorithm was derived based on recursive least squares technique that are widely used in data processing applications (Simon, D, 2006). Usage recursive least squares filter, makes possible to process a new set of observational data, without reprocessing data, which has been processed before. Specific feature of such approach is that number of observation in data set may be variable. This feature makes recursive least squares filter more flexible approach compare to batch least squares (process complete set of observations in each iteration) and Kalman filtering (suppose updating state vector on each epoch with measurements).Advantages of proposed approach are demonstrated by processing of real astrometric observations of near Earth asteroids. The case of 2008 TC3 was studied. 2008 TC3 was discovered just before its impact with Earth. There are a many closely spaced observations of 2008 TC3 on the interval between discovering and impact, which creates favorable conditions for usage of recursive approaches. Each of approaches has very similar precision in case of 2008 TC3. At the same time, recursive least squares approaches have much higher performance. Thus, this approach more favorable for orbit fitting of a celestial body, which was detected shortly before the collision or close approach to the Earth.This work was carried out at MIIGAiK and supported by the Russian Science Foundation, Project no. 14-22-00197.References:O. Montenbruck and E. Gill, "Satellite Orbits, Models, Methods and Applications," Springer-Verlag, 2000, pp. 1-369.D. Simon, "Optimal State Estimation

  12. Radar Observations and the Shape of 2008 EV5: Ridges and Craters on Near-Earth Asteroids

    Science.gov (United States)

    Busch, Michael W.; Ostro, S. J.; Benner, L. A. M.; Scheeres, D. J.; Giorgini, J. D.; Brozovic, M.; Nolan, M. C.; Howell, E. S.; Taylor, P. A.; Margot, J.; Magri, C.; Jao, J. S.; Brisken, W.

    2010-10-01

    The near-Earth asteroid 2008 EV5 was discovered by the Mt. Lemmon Survey on March 4 2008, and approached to within 8.4 lunar distances in December 2008, when it was a very strong radar target. We observed EV5 with the Arecibo and Goldstone planetary radars and the Very Long Baseline Array, and previously described those observations and obtaining EV5's pole direction. We have now completed a detailed model of EV5's shape. The Arecibo delay-Doppler data provided 7.5-m spatial resolution, showing that EV5's overall shape is a 400 ± 50 m spheroid. The most prominent surface feature is a ridge parallel to the asteroid's equator that is broken by a concavity 150 m in diameter. Otherwise the asteroid's surface is shows few decameter-scale features and is notably smooth - our shape model has an average surface slope of <15º. EV5's radar and optical albedos are consistent with either rocky or stony-iron composition. EV5's ridge is similar to structure seen on the rubble-pile near-Earth asteroid (66391) 1999 KW4, and is consistent with YORP spin-up reconfiguring the asteroid during an episode of more rapid rotation. We interpret the concavity as an impact crater. Shaking during the impact should have erased smaller surface features and may explain the general lack of decameter-scale surface structure.

  13. Jupiter family comets in near-Earth orbits: Are some of them interlopers from the asteroid belt?

    Science.gov (United States)

    Fernández, Julio A.; Sosa, Andrea

    2015-12-01

    We analyze a sample of 58 Jupiter family comets (JFCs) in near-Earth orbits, defined as those whose perihelion distances at the time of discovery were qdisc newcomers in the near-Earth region. Yet, a minor fraction of JFCs (less than about one third) are found to move on stable orbits for the past ∼ 104 yr, and in some cases are found to continue to be stable at 5 × 104 yr in the past. They also avoid very close encounters with Jupiter. Their orbital behavior is very similar to that of NEAs in cometary orbits. While "typical" JFCs in unstable orbits probably come from the trans-Neptunian region, the minor group of JFCs in asteroidal orbits may come from the main asteroid belt, like the NEAs. The asteroidal JFCs may have a more consolidated structure and a higher mineral content than that of comets coming from the trans-Neptunian belt or the Oort cloud, which could explain their much longer physical lifetimes in the near-Earth region. In particular, we mention comets 66P/du Toit, 162P/Siding Spring, 169P/NEAT, 182P/LONEOS, 189P/NEAT, 249P/LINEAR, 300P/Catalina, and P/2003 T12 (SOHO) as the most likely candidates to have an origin in the main asteroid belt. Another interesting case is 207P/NEAT, which stays near the 3:2 inner mean motion resonance with Jupiter, possibly evolving from the Hilda asteroid zone.

  14. Increasing the Output of Spacewatch Astrometry of Near-Earth Asteroids

    Science.gov (United States)

    McMillan, Robert S.; Bressi, Terrence H.; Larsen, Jeffrey A.; Mastaler, Ronald A.; Read, Michael T.; Tubbiolo, Andrew F.; Scotti, James V.

    2016-10-01

    The Spacewatch Project at the University of Arizona specializes in followup astrometry of Near-Earth Asteroids (NEAs) when they are fainter than most other followup stations can reach. Priority is given to objects on the Confirmation Page of the Minor Planet Center (MPC), potential impactors on the Earth, objects requested by the Jet Propulsion Laboratory (JPL), future targets of radar, objects whose infrared flux or taxonomic properties have been measured, potential destinations of spacecraft, and objects being monitored for Yarkovsky drift. Upgrades in hardware, software, and observing procedures since 2015 Sept have boosted the numbers of observations of NEAs we make with the 0.9-m, 1.8-m, and 2.3-m telescopes on Kitt Peak in Arizona. Targeting specific NEAs with our 0.9-m telescope (site code 691) down to V magnitude 22 has increased the rate of observations of NEAs by a factor of 3.9 compared to the previous survey pattern. Comparing the first three months of 2016 with the same period in 2015 our 1.8-m telescope (site code 291) shows a 25% increase in total images acquired, a 35% increase in shutter-open exposure time, a 68% increase in the number of PHAs observed down to R magnitude 22.5, and a 105% increase in the number of PHAs observed with magnitudes >= 21.5. Installation of our new CCD camera at the Cassegrain focus of the Bok 2.3-meter telescope of Steward Observatory (site code ^695) and better software have allowed 50% more targeted objects per night down to R magnitude 23 and a 303% increase in the number of images taken per night. In the time interval reported, Spacewatch observed 41% of all the NEAs that were observed by anyone and 44% of all the PHAs that were observed by anyone. We also contributed 19% of all the astrometry of PHAs that were fainter than magnitude 22. Support of Spacewatch is from NASA/NEOO grants, the Lunar and Planetary Laboratory, Steward Observatory, Kitt Peak National Observatory, the Brinson Foundation of Chicago, IL, the

  15. NEEMO 15: Evaluation of human exploration systems for near-Earth asteroids

    Science.gov (United States)

    Chappell, Steven P.; Abercromby, Andrew F.; Gernhardt, Michael L.

    2013-08-01

    The NASA Extreme Environment Mission Operations (NEEMO) 15 mission was focused on evaluating techniques for exploring near-Earth asteroids (NEAs). It began with a University of Delaware autonomous underwater vehicle (AUV) systematically mapping the coral reef for hundreds of meters surrounding the Aquarius habitat. This activity is akin to the type of "far-field survey" approach that may be used by a robotic precursor in advance of a human mission to a NEA. Data from the far-field survey were then examined by the NEEMO science team and follow-up exploration traverses were planned, which used Deepworker single-person submersibles. Science traverses at NEEMO 15 were planned according to a prioritized list of objectives developed by the science team. These objectives were based on review and discussion of previous related marine science research, including previous marine science saturation missions conducted at the Aquarius habitat. AUV data were used to select several areas of scientific interest. The Deepworker science traverses were then executed at these areas of interest during 4 days of the NEEMO 15 mission and provided higher resolution data such as coral species distribution and mortality. These traverses are analogous to the "near-field survey" approach that is expected to be performed by a Multi-Mission Space Exploration Vehicle (MMSEV) during a human mission to a NEA before extravehicular activities (EVAs) are conducted. In addition to the science objectives that were pursued, the NEEMO 15 traverses provided an opportunity to test newly developed software and techniques. Sample collection and instrument deployment on the NEA surface by EVA crew would follow the "near-field survey" in a human NEA mission. Sample collection was not necessary for the purposes of the NEEMO science objectives; however, the engineering and operations objectives during NEEMO 15 were to evaluate different combinations of vehicles, crew members, tools, and equipment that could be

  16. Desert RATS 2011: Human and robotic exploration of near-Earth asteroids

    Science.gov (United States)

    Abercromby, Andrew F. J.; Chappell, Steven P.; Gernhardt, Michael L.

    2013-10-01

    The Desert Research and Technology Studies (D-RATS) 2011 field test involved the planning and execution of a series of exploration scenarios under operational conditions similar to those expected during a human exploration mission to a near-Earth asteroid (NEA). The focus was on understanding the operations tempo during simulated NEA exploration and the implications of communications latency and limited data bandwidth. Anchoring technologies and sampling techniques were not evaluated due to the immaturity of those technologies and the inability to meaningfully test them at D-RATS. Reduced gravity analogs and simulations are being used to fully evaluate Space Exploration Vehicle (SEV) and extravehicular (EVA) operations and interactions in near-weightlessness at a NEA as part of NASA's integrated analogs program. Hypotheses were tested by planning and performing a series of 1-day simulated exploration excursions comparing test conditions all of which involved a single Deep Space Habitat (DSH) and either 0, 1, or 2 SEVs; 3 or 4 crewmembers; 1 of 2 different communications bandwidths; and a 50-second each-way communications latency between the field site and Houston. Excursions were executed at the Black Point Lava Flow test site with a remote Mission Control Center and Science Support Room at Johnson Space Center (JSC) being operated with 50-second each-way communication latency to the field. Crews were composed of astronauts and professional field geologists. Teams of Mission Operations and Science experts also supported the mission simulations each day. Data were collected separately from the Crew, Mission Operations, and Science teams to assess the test conditions from multiple perspectives. For the operations tested, data indicates practically significant benefits may be realized by including at least one SEV and by including 4 versus 3 crewmembers in the NEA exploration architecture as measured by increased scientific data quality, EVA exploration time

  17. Thermal Emission Spectroscopy (5.2 To 38 Microns) And Analysis Of 10 Near-earth Asteroids

    Science.gov (United States)

    Dave, Riddhi; Emery, J.; Cruikshank, D.; Mueller, M.; Delbo, M.; Trilling, D. E.; Mommert, M.

    2010-10-01

    Near Earth Asteroids (NEAs- 0.983AUSolar System. Information about the albedo and size distribution of the NEAs is an essential prerequisite for exploring their physical nature, thermal properties, mineralogy, taxonomy and for developing reliable NEA population models. In support of the ExploreNEOs campaign of the Warm Spitzer program, we will present initial results from study of a sample of NEAs using the Infrared Spectrograph (IRS) on NASA's Spitzer Space Telescope [Programs 88 and 91- Extinct Comets and Low-Albedo Asteroids]. These data were reduced with Spitzer IRS Custom Extraction (SPICE) a JAVA-based tool built for interactive extraction of Spitzer IRS spectra. The 5.2-38 m thermal emission spectra[R 60-130] have been fitted with models of the thermal continuum employing the Near Earth Asteroid Thermal Model [NEATM](Harris 1998) and a Thermophysical model. Simultaneous measurements of the asteroid flux in the thermal infrared, combined with a thermal model, allow both the diameter and the albedo to be determined. The sample of Asteroids to be a part of this study are 1602 Geographos, 1580 Betulia, 433 Eros, 2212 Hephaistos, 1685 Toro, 1917 Cuyo, 1566 Icarus, 3200 Phaethon, 7092 Cadmus and 1866 Sisyphus. This study will give in-depth understanding of the applicability of the NEATM for NEAs observed at higher phase angles, having larger thermal inertia than main-belt asteroids, and/or displaying varied geometries. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA.

  18. NASA's Human Mission to a Near-Earth Asteroid: Landing on a Moving Target

    Science.gov (United States)

    Smith, Jeffrey H.; Lincoln, William P.; Weisbin, Charles R.

    2011-01-01

    This paper describes a Bayesian approach for comparing the productivity and cost-risk tradeoffs of sending versus not sending one or more robotic surveyor missions prior to a human mission to land on an asteroid. The expected value of sample information based on productivity combined with parametric variations in the prior probability an asteroid might be found suitable for landing were used to assess the optimal number of spacecraft and asteroids to survey. The analysis supports the value of surveyor missions to asteroids and indicates one launch with two spacecraft going simultaneously to two independent asteroids appears optimal.

  19. NASA's Human Mission to a Near-Earth Asteroid: Landing on a Moving Target

    Science.gov (United States)

    Smith, Jeffrey H.; Lincoln, William P.; Weisbin, Charles R.

    2011-01-01

    This paper describes a Bayesian approach for comparing the productivity and cost-risk tradeoffs of sending versus not sending one or more robotic surveyor missions prior to a human mission to land on an asteroid. The expected value of sample information based on productivity combined with parametric variations in the prior probability an asteroid might be found suitable for landing were used to assess the optimal number of spacecraft and asteroids to survey. The analysis supports the value of surveyor missions to asteroids and indicates one launch with two spacecraft going simultaneously to two independent asteroids appears optimal.

  20. High-Resolution Bistatic Radar Imaging of Near-Earth Asteroids in 2015 using New Capabilities of Goldstone and Green Bank Telescopes

    Science.gov (United States)

    Naidu, S.; Benner, L.; Brozovic, M.; Giorgini, J. D.; Jao, J. S.; Lee, C. G.; Busch, M.; Ghigo, F. D.; Ford, A.; Kobelski, A.; Marshall, S.

    2015-12-01

    We present new results from bistatic Goldstone to Green Bank Telescope (GBT) high-resolution radar imaging of near-Earth asteroids (NEAs). Previously, most radar observations used either the 305-m Arecibo radar or the 70-m DSS-14 radar at Goldstone. Following the installation of new data-taking equipment at the GBT in late 2014, the number of bistatic Goldstone/GBT observations has increased substantially. Receiving Goldstone radar echoes at the 100-m GBT improves the signal-to-noise ratios (SNRs) two- to three-fold relative to monostatic reception at DSS-14. The higher SNRs allow us to obtain higher resolution images than is possible with DSS-14 both transmitting and receiving. Thus far in 2015, we have used the GBT receiver in combination with the 450 kW DSS-14 antenna and a new low-power 80kW transmitter on the 34-m DSS-13 antenna at the Goldstone complex to image five and two NEAs respectively. Asteroids 2005 YQ96, 2004 BL86, and 1994 AW1 are binary systems. 2011 UW158 has a spin period of 36 minutes that is unusually fast among asteroids its size (~500 m). 1999 JD6 is a deeply bifurcated double-lobed object. 2015 HM10 is an elongated 80 m asteroid with a spin period of 22 minutes. Our best images of these objects resolve the surface with resolutions of 3.75 m and reveal numerous features. Such images are useful to estimate the 3D shape, spin state, and other physical and dynamical properties of the objects. This knowledge is of particular interest for spacecraft mission planning, impact threat assessment, and resource utilization. Over the long term, such observations will help answer fundamental questions regarding the origin of the diversity in asteroid morphologies, the importance of spin-up mechanisms and collisional influences, the interior structure and thermal properties of asteroids, and the variety of dynamical states.

  1. NEOCAM: Near Earth Object Chemical Analysis Mission: Bridging the Gulf between Telescopic Observations and the Chemical and Mineralogical Compositions of Asteroids or Diogenes A: Diagnostic Observation of the Geology of Near Earth Spectrally-Classified Asteroids

    Science.gov (United States)

    Nuth, Joseph A.

    2009-01-01

    Studies of meteorites have yielded a wealth of scientific information based on highly detailed chemical and isotopic studies possible only in sophisticated terrestrial laboratories. Telescopic studies have revealed an enormous (greater than 10(exp 5)) number of physical objects ranging in size from a few tens of meters to several hundred kilometers, orbiting not only in the traditional asteroid belt between Mars and Jupiter but also throughout the inner solar system. Many of the largest asteroids are classed into taxonomic groups based on their observed spectral properties and are designated as C, D. X, S or V types (as well as a wide range in sub-types). These objects are certainly the sources far the meteorites in our laboratories, but which asteroids are the sources for which meteorites? Spectral classes are nominally correlated to the chemical composition and physical characteristics of the asteroid itself based on studies of the spectral changes induced in meteorites due to exposure to a simulated space environment. While laboratory studies have produced some notable successes (e.g. the identification of the asteroid Vesta as the source of the H, E and D meteorite classes), it is unlikely that we have samples of each asteroidal spectral type in our meteorite collection. The correlation of spectral type and composition for many objects will therefore remain uncertain until we can return samples of specific asteroid types to Earth for analyses. The best candidates for sample return are asteroids that already come close to the Earth. Asteroids in orbit near 1 A.U. have been classified into three groups (Aten, Apollo & Amor) based on their orbital characteristics. These Near Earth Objects (NEOs) contain representatives of virtually all spectral types and sub-types of the asteroid population identified to date. Because of their close proximity to Earth, NEOs are prime targets for asteroid missions such as the NEAR-Shoemaker NASA Discovery Mission to Eros and the

  2. Earth encounters as the origin of fresh surfaces on near-Earth asteroids.

    Science.gov (United States)

    Binzel, Richard P; Morbidelli, Alessandro; Merouane, Sihane; Demeo, Francesca E; Birlan, Mirel; Vernazza, Pierre; Thomas, Cristina A; Rivkin, Andrew S; Bus, Schelte J; Tokunaga, Alan T

    2010-01-21

    Telescopic measurements of asteroids' colours rarely match laboratory reflectance spectra of meteorites owing to a 'space weathering' process that rapidly reddens asteroid surfaces in less than 10(6) years. 'Unweathered' asteroids (those having spectra matching the most commonly falling ordinary chondrite meteorites), however, are seen among small bodies the orbits of which cross inside Mars and the Earth. Various explanations have been proposed for the origin of these fresh surface colours, ranging from collisions to planetary encounters. Less reddened asteroids seem to cross most deeply into the terrestrial planet region, strengthening the evidence for the planetary-encounter theory, but encounter details within 10(6) years remain to be shown. Here we report that asteroids displaying unweathered spectra (so-called 'Q-types') have experienced orbital intersections closer than the Earth-Moon distance within the past 5 x 10(5) years. These Q-type asteroids are not currently found among asteroids showing no evidence of recent close planetary encounters. Our results substantiate previous work: tidal stress, strong enough to disturb and expose unweathered surface grains, is the most likely dominant short-term asteroid resurfacing process. Although the seismology details are yet to be worked out, the identification of rapid physical processes that can produce both fresh and weathered asteroid surfaces resolves the decades-long puzzle of the difference in colour of asteroids and meteorites.

  3. Physical Characterization of ~2-meter Diameter Near-Earth Asteroid 2015 TC25: A possible boulder from E-type Asteroid (44) Nysa

    CERN Document Server

    Reddy, Vishnu; Bottke, William F; Thirouin, Audrey; Rivera-Valentin, Edgard G; Kelley, Michael S; Ryan, William; Cloutis, Edward A; Tegler, Stephen C; Ryan, Eileen V; Taylor, Patrick A; Richardson, James E; Moskovitz, Nicholas; Corre, Lucille Le

    2016-01-01

    Small near-Earth asteroids (>20 meters) are interesting because they are progenitors for meteorites in our terrestrial collection. Crucial to our understanding of the effectiveness of our atmosphere in filtering low-strength impactors is the physical characteristics of these small near-Earth asteroids (NEAs). In the past, characterization of small NEAs has been a challenge because of the difficulty in detecting them prior to close Earth flyby. In this study we physically characterized the 2-meter diameter near-Earth asteroid 2015 TC25 using ground-based optical, near-infrared and radar assets during a close flyby of the Earth (distance 69,000 miles) in Oct. 2015. Our observations suggest that its surface composition is similar to aubrites, a rare class of high albedo differentiated meteorites. Aubrites make up only 0.14 % of all know meteorites in our terrestrial meteorite collection. 2015 TC25 is also a very fast rotator with a rotation period of 133 seconds. We compared spectral and dynamical properties of ...

  4. Near Earth Asteroid Human Mission Possibilities Using Nuclear Thermal Rocket (NTR) Propulsion

    Science.gov (United States)

    Borowski, Stanley; McCurdy, David R.; Packard, Thomas W.

    2012-01-01

    The NTR is a proven technology that generates high thrust and has a specific impulse (Isp (is) approximately 900 s) twice that of today's best chemical rockets. During the Rover and NERVA (Nuclear Engine for Rocket Vehicle Applications) programs, twenty rocket reactors were designed, built and ground tested. These tests demonstrated: (1) a wide range of thrust; (2) high temperature carbide-based nuclear fuel; (3) sustained engine operation; (4) accumulated lifetime; and (5) restart capability - all the requirements needed for a human mission to Mars. Ceramic metal fuel was also evaluated as a backup option. In NASA's recent Mars Design reference Architecture (DRA) 5.0 study, the NTR was selected as the preferred propulsion option because of its proven technology, higher performance, lower launch mass, versatile vehicle design, simple assembly, and growth potential. In contrast to other advanced propulsion options, NTP requires no large technology scale-ups. In fact, the smallest engine tested during the Rover program - the 25 klbf 'Pewee' engine is sufficient for a human Mars mission when used in a clustered engine configuration. The 'Copernicus crewed NTR Mars transfer vehicle design developed for DRA 5.0 has significant capability that can enable reusable '1-year' round trip human missions to candidate near Earth asteroids (NEAs) like 1991 JW in 2027, or 2000 SG344 and Apophis in 2028. A robotic precursor mission to 2000 SG344 in late 2023 could provide an attractive Flight Technology Demonstration of a small NTR engine that is scalable to the 25 klbf-class engine used for human missions 5 years later. In addition to the detailed scientific data gathered from on-site inspection, human NEA missions would also provide a valuable 'check out' function for key elements of the NTR transfer vehicle (its propulsion module, TransHab and life support systems, etc.) in a 'deep space' environment prior to undertaking the longer duration Mars orbital and landing missions that

  5. BILLIARDS: A Demonstration Mission for Hundred-Meter Class Near Earth Asteroid Disruption

    Science.gov (United States)

    Marcus, Matthew; Sloane, Joshua; Ortiz, Oliver; Barbee, Brent W.

    2015-01-01

    Currently, no planetary defense demonstration mission has ever been flown. While Nuclear Explosive Devices (NEDs) have significantly more energy than a kinetic impactor launched directly from Earth, they present safety and political complications, and therefore may only be used when absolutely necessary. The Baseline Instrumented Lithology Lander, Inspector, and Asteroid Redirection Demonstration System (BILLIARDS) is a demonstration mission for planetary defense, which is capable of delivering comparable energy to the lower range of NED capabilities in the form of a safer kinetic impactor. A small asteroid (disrupt the larger asteroid. To reduce the cost and complexity, an asteroid pair which has a natural close approach is selected.

  6. ExploreNEOs: Average albedo by taxonomic complex in the near-Earth asteroid population

    NARCIS (Netherlands)

    Thomas, C. A.; Trilling, D. E.; Emery, J. P.; Mueller, M.; Hora, J. L.; Benner, L. A. M.; Bhattacharya, B.; Bottke, W. F.; Chesley, S.; Delbo, M.; Fazio, G.; Harris, A. W.; Mainzer, A.; Mommert, M.; Morbidelli, A.; Penprase, B.; Smith, H. A.; Spahr, T. B.; Stansberry, J. A.

    2011-01-01

    Understanding the albedo distribution of the Near- Earth Object (NEO) population allows for a better understanding of the relationship between absolute magnitude and size, which impacts calculations of size frequency distribution and impact hazards. Examining NEO albedos also sheds light on the diff

  7. ExploreNEOs: Average albedo by taxonomic complex in the near-Earth asteroid population

    NARCIS (Netherlands)

    Thomas, C. A.; Trilling, D. E.; Emery, J. P.; Mueller, M.; Hora, J. L.; Benner, L. A. M.; Bhattacharya, B.; Bottke, W. F.; Chesley, S.; Delbo, M.; Fazio, G.; Harris, A. W.; Mainzer, A.; Mommert, M.; Morbidelli, A.; Penprase, B.; Smith, H. A.; Spahr, T. B.; Stansberry, J. A.

    2011-01-01

    Understanding the albedo distribution of the Near- Earth Object (NEO) population allows for a better understanding of the relationship between absolute magnitude and size, which impacts calculations of size frequency distribution and impact hazards. Examining NEO albedos also sheds light on the

  8. Conjunction Risks of Near-Earth Objects to Artificial Satellites: The Case of Asteroid 2015 VY105

    Science.gov (United States)

    Ryan, W.; Ryan, E.

    2016-09-01

    The close approach of near-Earth object 2015 VY105 on November 15, 2015 occurred less than 24 hours after discovery by the Catalina Sky Survey (located in Tucson, AZ). Based on the discovery metric information and follow up data from Magdalena Ridge Observatory (MRO) observations, it was clear that this asteroid would pass through the geostationary satellite belt. In particular, data indicated that although 2015 VY105 would come within approximately 200 km of the DirectTV 11 and 14 satellites, it would not impact either. The details of this analysis as well as characterization results acquired are presented. Further, examples of various other asteroids that have made close approaches within geostationary distances in the past (with both long and short lead times) are included for risk context.

  9. Mitigation-relevant science with Don Quijote - a European-led mission to a near-Earth asteroid

    Science.gov (United States)

    Harris, A. W.; Galvez, A.; Benz, W.; Fitzsimmons, A.; Green, S. F.; Michel, P.; Valsecchi, G.; Paetzold, M.; Haeusler, B.; Carnelli, I.

    The Don Quijote concept includes a rendezvous spacecraft and an impactor vehicle The main aim of the mission is to carry out an experiment to demonstrate the modification of a near-Earth asteroid s orbit in a controlled way as a first step in establishing mitigation measures against an eventual hazardous object In particular the spacecraft would study the physical properties of the target asteroid and the effects of a kinetic impact on its dynamical state It is also expected that some spacecraft resources will be available for more general solar-system science investigations The Don Quijote mission is currently at the phase-A stage during which a number of European consortia of industrial and scientific partners will study its technical feasibility and potential scientific return The basic mission concept current scientific issues and the possibilities for international participation in the mission will be discussed

  10. On the rotation rates and axis ratios of the smallest known near-Earth asteroids---the archetypes of the Asteroid Redirect Mission targets

    CERN Document Server

    Hatch, Patrick

    2015-01-01

    NASA's Asteroid Redirect Mission (ARM) has been proposed with the aim to capture a small asteroid a few meters in size and redirect it into an orbit around the Moon. There it can be investigated at leisure by astronauts aboard an Orion or other spacecraft. The target for the mission has not yet been selected, and there are very few potential targets currently known. Though sufficiently small near-Earth asteroids (NEAs) are thought to be numerous, they are also difficult to detect and characterize with current observational facilities. Here we collect the most up-to-date information on the smallest known near-Earth asteroids to outline the properties of these small NEAs as currently understood, in order to examine what the eventual ARM target might be like. Observational biases certainly mean that our sample is not an ideal representation of the true population of small NEAs. However our sample is representative of the eventual target list for the ARM mission, which will be compiled under very similar observa...

  11. Surface composition and taxonomic classification of a group of near-Earth and Mars-crossing asteroids

    CERN Document Server

    Sanchez, Juan A; Reddy, Vishnu; Nathues, Andreas

    2013-01-01

    In the past, constraining the surface composition of near-Earth asteroids (NEAs) has been difficult due to the lack of high quality near-IR spectral data (0.7-2.5 microns) that contain mineralogically diagnostic absorption bands. Here we present visible (0.43-0.95 microns) and near-infrared (0.7-2.5 microns) spectra of nine NEAs and five Mars-crossing asteroids (MCs). The studied NEAs are: 4055 Magellan, 19764 (2000 NF5), 89830 (2002 CE), 138404 (2000 HA24), 143381 (2003 BC21), 159609 (2002 AQ3), 164121 (2003 YT1), 241662 (2000 KO44) and 2007 ML13. The studied MCs are: 1656 Suomi, 2577 Litva, 5407 (1992 AX), 22449 Ottijeff and 47035 (1998 WS). The observations were conducted with the NTT at La Silla, Chile, the 2.2 m telescope at Calar Alto, Spain, and the IRTF on Mauna Kea, Hawai'i. The taxonomic classification (Bus system) of asteroids showed that all observed MC asteroids belong to the S-complex, including the S, Sr and Sl classes. Seven of the NEAs belong to the S-complex, including the S, Sa, Sk and Sl c...

  12. Mining the ESO WFI and INT WFC archives for known Near Earth Asteroids. Mega-Precovery software

    Science.gov (United States)

    Vaduvescu, O.; Popescu, M.; Comsa, I.; Paraschiv, A.; Lacatus, D.; Sonka, A.; Tudorica, A.; Birlan, M.; Suciu, O.; Char, F.; Constantinescu, M.; Badescu, T.; Badea, M.; Vidican, D.; Opriseanu, C.

    2013-08-01

    The ESO/MPG WFI and the INT WFC wide field archives comprising 330 000 images were mined to search for serendipitous encounters of known Near Earth Asteroids (NEAs) and Potentially Hazardous Asteroids (PHAs). A total of 152 asteroids (44 PHAs and 108 other NEAs) were identified using the PRECOVERY software, their astrometry being measured on 761 images and sent to the Minor Planet Centre. Both recoveries and precoveries were reported, including prolonged orbital arcs for 18 precovered objects and 10 recoveries. We analyze all new opposition data by comparing the orbits fitted before and after including our contributions. We conclude the paper presenting "Mega-Precovery", a new online service focused on data mining of many instrument archives simultaneously for one or a few given asteroids. A total of 28 instrument archives have been made available for mining using this tool, adding together about 2.5 million images forming the "Mega-Archive". Using ESO/MPG WFI images served by the ESO Science Archive Facility and INT WFC images served by the CASU Astronomical Data Centre.

  13. Physical Characterization of ˜2 M Diameter Near-Earth Asteroid 2015 TC25: A Possible Boulder from E-type Asteroid (44) Nysa

    Science.gov (United States)

    Reddy, Vishnu; Sanchez, Juan A.; Bottke, William F.; Thirouin, Audrey; Rivera-Valentin, Edgard G.; Kelley, Michael S.; Ryan, William; Cloutis, Edward A.; Tegler, Stephen C.; Ryan, Eileen V.; Taylor, Patrick A.; Richardson, James E.; Moskovitz, Nicholas; Le Corre, Lucille

    2016-12-01

    Small near-Earth asteroids (NEAs) (differentiated meteorites. Aubrites make up only 0.14% of all known meteorites in our terrestrial meteorite collection. 2015 TC25 is also a very fast rotator with a period of 133 ± 6 s. We combined the spectral and dynamical properties of 2015 TC25 and found the best candidate source body in the inner main belt to be the 70 km diameter E-type asteroid (44) Nysa. We attribute the difference in spectral slope between the two objects to the lack of regolith on the surface of 2015 TC25. Using the albedo of E-type asteroids (50%-60%) we refine the diameter of 2015 TC25 to 2 m, making it one of the smallest NEAs ever to be characterized.

  14. Detection of Yarkovsky effect and solar radiation pressure on Near-Earth Asteroids

    Science.gov (United States)

    Faggioli, Laura; Del Vigna, Alessio; Milani, Andrea; Spoto, Federica; Valsecchi, Giovanni B.

    2016-10-01

    The orbit of small-sized asteroids can be affected by non-gravitational perturbations. When this happens, non-gravitational forces need to be taken into account since they are as important as collisions and gravitational perturbations for the overall understanding of the asteroid orbital evolution.The Yarkovsky effect and the Solar Radiation Pressure (SRP) are non-gravitational perturbations that can be modelled knowing the physical properties of asteroids, and whose consequences of the motions can be measured from accurate astrometry.The knowledge of the physical properties of asteroids is usually not sufficient to produce the thermophysical models needed for the computation of the Yarkovsky acceleration. Nevertheless, it can often be measured as a semimajor axis drift if the astrometric dataset contains extremely accurate observations (e.g. radar data), or if the observations span a sufficiently long time interval.Farnocchia et al. 2013 list 21 NEAs with a measurable semimajor-axis drift. Since 2013, the number of asteroids for which it is possible to detect the Yarkovsky effect has grown. This is due to the increased quality and time span of the observations, and to new radar measurements that have since become available. We are able to detect the Yarkovsky effect for more than 40 NEAs, employing a high precision dynamical model, including the Newtonian attraction of 16 massive asteroids and the planetary relativistic terms, and a suitable astrometric data treatment. We present a list of objects with a significant detection of Yarkovksy effect and a value compatible with the Yarkovsky mechanism.The computed non-gravitational perturbations will be added to the web portal of the ESA SSA-NEO Coordination Centre, highlighting the fact that the orbit has been computed taking the Yarkovsky effect or the SRP into account. The inclusion of non-gravitational perturbations can also affect the results of the impact monitoring, as in the case of (410777) 2009 FD, (29075

  15. Method for Calculating Orbits of Near-Earth Asteroids Observed with Telescope OMT-800

    Science.gov (United States)

    Troianskyi, V. V.; Bazyey, A. A.; Kashuba, V. I.; Zhukov, V. V.; Korzhavin, S. A.

    One of the frame processing techniques, as well as an example of further use of the obtained results to calculate an asteroid's orbit are given in the present paper. The application of frame combination method to improve the telescope's limiting magnitude is described.

  16. Human Expeditions to Near-Earth Asteroids: An Update on NASA's Status and Proposed Activities for Small Body Exploration

    Science.gov (United States)

    Abell, Paul; Mazanek, Dan; Barbee, Brent; Landis, Rob; Johnson, Lindley; Yeomans, Don; Reeves, David; Drake, Bret; Friedensen, Victoria

    2013-01-01

    Over the past several years, much attention has been focused on the human exploration of near-Earth asteroids (NEAs). Two independent NASA studies examined the feasibility of sending piloted missions to NEAs, and in 2009, the Augustine Commission identified NEAs as high profile destinations for human exploration missions beyond the Earth- Moon system as part of the Flexible Path. More recently the current U.S. presidential administration directed NASA to include NEAs as destinations for future human exploration with the goal of sending astronauts to a NEA in the mid to late 2020s. This directive became part of the official National Space Policy of the United States of America as of June 28, 2010. The scientific and hazard mitigation benefits, along with the programmatic and operational benefits of a human venture beyond the Earth-Moon system, make a mission to a NEA using NASA s proposed exploration systems a compelling endeavor.

  17. Human Missions to Near-Earth Asteroids: An Update on NASA's Current Status and Proposed Activities for Small Body Exploration

    Science.gov (United States)

    Abell, P. A.; Mazanek, D. D.; Barbee, B. W.; Mink, R. G.; Landis, R. R.; Adamo, D. R.; Johnson, L. N.; Yeomans, D. K.; Reeves, D. M.; Larman, K. T.; Drake, B. G.; Friedensen, V. P.

    2012-01-01

    Over the past several years, much attention has been focused on the human exploration of near-Earth asteroids (NEAs). Two independent NASA studies examined the feasibility of sending piloted missions to NEAs, and in 2009, the Augustine Commission identified NEAs as high profile destinations for human exploration missions beyond the Earth-Moon system as part of the Flexible Path. More recently the current U.S. presidential administration directed NASA to include NEAs as destinations for future human exploration with the goal of sending astronauts to a NEA in the mid to late 2020s. This directive became part of the official National Space Policy of the United States of America as of June 28, 2010.

  18. Mission Analysis for Multiple Rendezvous of Near-Earth Asteroids Using Earth Gravity Assist

    Science.gov (United States)

    2010-03-01

    and there are potentially undiscovered thousands. This creates what many call an interstellar “shooting gallery” within which the Earth...continually travels . William Napier, in the article Hazards from Comets and Asteroids (as cited in Bostrom, and, Cirkovic, 2008) writes, “Multiplying the low... travel and the like. Unlike these more mundane risks, however, the impact hazard is unbounded: a big one could end civilization (2008: 234).” The

  19. Thermal properties and an improved shape model for near-Earth asteroid (162421) 2000 ET70

    Science.gov (United States)

    Marshall, Sean E.; Howell, Ellen S.; Magri, Christopher; Vervack, Ronald J.; Campbell, Donald B.; Fernández, Yanga R.; Nolan, Michael C.; Crowell, Jenna L.; Hicks, Michael D.; Lawrence, Kenneth J.; Taylor, Patrick A.

    2017-08-01

    We present thermal properties and an improved shape model for potentially hazardous asteroid (162421) 2000 ET70. In addition to the radar data from 2000 ET70's apparition in 2012, our model incorporates optical lightcurves and infrared spectra that were not included in the analysis of Naidu et al. (2013, Icarus 226, 323-335). We confirm the general ;clenched fist; appearance of the Naidu et al. model, but compared to their model, our best-fit model is about 10% longer along its long principal axis, nearly identical along the intermediate axis, and about 25% shorter along the short axis. We find the asteroid's dimensions to be 2.9 km × 2.2 km × 1.5 km (with relative uncertainties of about 10%, 15%, and 25%, respectively). With the available data, 2000 ET70's period and pole position are degenerate with each other. The radar and lightcurve data together constrain the pole direction to fall along an arc that is about twenty-three degrees long and eight degrees wide. Infrared spectra from the NASA InfraRed Telescope Facility (IRTF) provide an additional constraint on the pole. Thermophysical modeling, using our SHERMAN software, shows that only a subset of the pole directions, about twelve degrees of that arc, are compatible with the infrared data. Using all of the available data, we find that 2000 ET70 has a sidereal rotation period of 8.944 h (± 0.009 h) and a north pole direction of ecliptic coordinates (52∘ , -60∘) ±6∘ . The infrared data, acquired over several dates, require that the thermal properties (albedo, thermal inertia, surface roughness) must change across the asteroid's surface. By incorporating the detailed shape model and spin state into our thermal modeling, the multiple ground-based observations at different viewing geometries have allowed us to constrain the levels of the variations in the surface properties of this asteroid.

  20. Bimodal Nuclear Thermal Rocket Sizing and Trade Matrix for Lunar, Near Earth Asteroid and Mars Missions

    Science.gov (United States)

    McCurdy, David R.; Krivanek, Thomas M.; Roche, Joseph M.; Zinolabedini, Reza

    2006-01-01

    The concept of a human rated transport vehicle for various near earth missions is evaluated using a liquid hydrogen fueled Bimodal Nuclear Thermal Propulsion (BNTP) approach. In an effort to determine the preliminary sizing and optimal propulsion system configuration, as well as the key operating design points, an initial investigation into the main system level parameters was conducted. This assessment considered not only the performance variables but also the more subjective reliability, operability, and maintainability attributes. The SIZER preliminary sizing tool was used to facilitate rapid modeling of the trade studies, which included tank materials, propulsive versus an aero-capture trajectory, use of artificial gravity, reactor chamber operating pressure and temperature, fuel element scaling, engine thrust rating, engine thrust augmentation by adding oxygen to the flow in the nozzle for supersonic combustion, and the baseline turbopump configuration to address mission redundancy and safety requirements. A high level system perspective was maintained to avoid focusing solely on individual component optimization at the expense of system level performance, operability, and development cost.

  1. Low Delta-V Near-Earth Asteroids: a survey of suitable targets for space missions

    CERN Document Server

    Ieva, S; Perna, D; Barucci, M A; Bernardi, F; Fornasier, S; De Luise, F; Perozzi, E; Rossi, A; Brucato, J R

    2014-01-01

    In the last decades Near-Earth Objects (NEOs) have become very important targets to study, since they can give us clues to the formation, evolution and composition of the Solar System. In addition, they may represent either a threat to humankind, or a repository of extraterrestrial resources for suitable space-borne missions. Within this framework, the choice of next-generation mission targets and the characterisation of a potential threat to our planet deserve special attention. To date, only a small part of the 11,000 discovered NEOs have been physically characterised. From ground and space-based observations one can determine some basic physical properties of these objects using visible and infrared spectroscopy. We present data for 13 objects observed with different telescopes around the world (NASA-IRTF, ESO-NTT, TNG) in the 0.4 - 2.5 um spectral range, within the NEOSURFACE survey (http://www.oa-roma.inaf.it/planet/NEOSurface.html). Objects are chosen from among the more accessible for a rendez-vous mis...

  2. Detection of Semi-Major Axis Drifts in 54 Near-Earth Asteroids: New Measurements of the Yarkovsky Effect

    CERN Document Server

    Nugent, C R; Chesley, S R; Vokrouhlický, D

    2012-01-01

    We have identified and quantified semi-major axis drifts in Near-Earth Asteroids (NEAs) by performing orbital fits to optical and radar astrometry of all numbered NEAs. We focus on a subset of 54 NEAs that exhibit some of the most reliable and strongest drift rates. Our selection criteria include a Yarkovsky sensitivity metric that quantifies the detectability of semi-major axis drift in any given data set, a signal-to-noise metric, and orbital coverage requirements. In 42 cases, the observed drifts (~10^-3 AU/Myr) agree well with numerical estimates of Yarkovsky drifts. This agreement suggests that the Yarkovsky effect is the dominant non-gravitational process affecting these orbits, and allows us to derive constraints on asteroid physical properties. In 12 cases, the drifts exceed nominal Yarkovsky predictions, which could be due to inaccuracies in our knowledge of physical properties, faulty astrometry, or modeling errors. If these high rates cannot be ruled out by further observations or improvements in m...

  3. Thermal Properties and an Improved Shape Model for Near-Earth Asteroid (162421) 2000 ET70

    CERN Document Server

    Marshall, Sean E; Magri, Christopher; Vervack, Ronald J; Campbell, Donald B; Fernández, Yanga R; Nolan, Michael C; Crowell, Jenna L; Hicks, Michael D; Lawrence, Kenneth J; Taylor, Patrick A

    2016-01-01

    We present thermal properties and an improved shape model for potentially hazardous asteroid (162421) 2000 ET70. In addition to the radar data from 2000 ET70's apparition in 2012, our model incorporates optical lightcurves and infrared spectra that were not included in the analysis of Naidu et al. (2013, Icarus 226, 323-335). We confirm the general "clenched fist" appearance of the previous model but find the asteroid's dimensions to be somewhat different at 2.90 km $\\times$ 2.24 km $\\times$ 1.50 km. In particular, the lightcurves favor a model that is significantly shorter along its z-axis (rotation axis) than the model of Naidu et al. With the available data, 2000 ET70's period and pole position are degenerate with each other. The radar and lightcurve data together constrain the pole direction to fall along an arc that is about thirty degrees long and nine degrees wide. Infrared spectra from the NASA InfraRed Telescope Facility (IRTF) provide an additional constraint on the pole. Thermophysical modeling, us...

  4. A Mobile Asteroid Surface Scout (MASCOT) on board the Hayabusa 2 Mission to the near Earth asteroid (162173) Ryugu

    Science.gov (United States)

    Jaumann, R.; Bibring, J. P.; Glassmeier, K. H.; Grott, M.; Ho, T. M.; Ulamec, S.; Schmitz, N.; Auster, H. U.; Biele, J.; Kuninaka, H.; Okada, T.; Yoshikawa, M.; Watanabe, S.; Spohn, T.; Koncz, A.; Hercik, D.; Michaelis, H.; Fujimoto, M.

    2016-12-01

    MASCOT is part of JAXA's Hayabusa 2 asteroid sample return mission that has been launched to asteroid (162173) Ryugu (1,2,3) on Dec 3rd, 2014. It is scheduled to arrive at Ryugu in 2018, and return samples to Earth in 2020. The German Aerospace Center (DLR) developed the lander MASCOT with contributions from CNES (France) (2,3). Ryugu has been classified as a Cg-type (4), believed to be a primitive volatile-rich remnant from the early solar system. Its visible geometric albedo is 0.07±0.01with a diameter of 0.87±0.03 km (5). The thermal inertia indicates thick dust with a cm-sized, gravel-dominated surface layer (5,6). Ryugu shows a retrograde rotation with a period of 7.63±0.01h. Spectral observations indicate iron-bearing phyllosilicates (1) on parts of the surface, suggesting compositional heterogeneity. MASCOT will enable to in-situ map the asteroid's geomorphology, the intimate structure, texture and composition of the regolith (dust, soil and rocks), and its thermal, mechanical, and magnetic properties in order to provide ground truth for the orbiter remote measurements, support the selection of sampling sites, and provide context information for the returned samples (2,3). MASCOT comprises a payload of four scientific instruments: camera, radiometer, magnetometer and hyperspectral microscope (2,3). Characterizing the properties of asteroid regolith in-situ will deliver important ground truth for further understanding telescopic and orbital observations as well as samples of asteroids. MASCOT will descend and land on the asteroid and will change its position by hopping (3). (1) Vilas, F., Astro. J. 1101-1105, 2008; (2) Jaumann, R., et al., SSR, DOI 10.1007/s11214-016-0263-2, 2016; (3) Ho, T.-M. et al., SSR, DOI 10.1007/s11214-016-0251-6, 2016; (4) Bus, S.J., Binzel, R.P. Icarus 158, 2002; (5) Hasegawa, T.G., et al., Astron. Soc. Japan 60, 2008; (6) T.G. Müller, T.G., et al., doi 10.1051/0004-6361/201015599, 2011.

  5. New Technologies and Strategies to Exploit Near Earth Asteroids for Breakthrough Space Development

    Science.gov (United States)

    Rather, John; Powell, James; Maise, George

    2010-01-01

    The past two decades have brought a profound expansion of knowledge of near earth objects (NEO). If creatively exploited, NEOs can significantly increase human safety while reducing costs of exploration and development of the moon, Mars and the solar system. Synergistically, the ability to defend the Earth from devastating impacts will become very effective. A spherical volume having a radius equivalent to the moon's orbit, 400,000 km, is visited every day by approximately ten NEOs having diameters of ~10 meters, while ~30 meter diameter encounters occur about once per month. Because these objects are usually very faint and only within detectable range for a few days, they require specialized equipment to discover them with high probability of detection and to enable accurate determination of orbital parameters. Survey systems are now being implemented that are cataloging many thousands of objects larger than 30 meters, but numerous advantages will result from extending the complete NEO census down to 10 meter diameters. The typical compositions of such NEOs will range from ~80% that are low density dust & rock ``rubble piles'' to perhaps 2% containing heavy metals-properties well known from meteorite samples. It is quite possible that there will also be some fragments of short period comets that are rich in water ice and other volatile components. In this paper we will propose a set of new technologies and strategies for exploiting NEO resources that can yield important space development breakthroughs at much lower costs than existing concepts. Solar powered ``Tugboats'' deployed at the space station can rendezvous with carefully selected NEOs and steer them into captured orbits in the lunar L4 & L5 regions. Robotic equipment will then modify them for a plethora of benefits. Notably, the problem of radiation shielding against the Van Allen belts, solar flares and cosmic rays will be solved. Free transportation from low earth orbit to the moon and beyond will be

  6. Mega-precovery and data mining of near-Earth asteroids and other Solar System objects

    Science.gov (United States)

    Popescu, M.; Vaduvescu, O.; Char, F.; Curelaru, L.; Euronear Team

    2014-07-01

    The vast collection of CCD images and photographic plate archives available from the world-wide archives and telescopes is still insufficiently exploited. Within the EURONEAR project we designed two data mining software with the purpose to search very large collections of archives for images which serendipitously include known asteroids or comets in their field, with the main aims to extend the arc and improve the orbits. In this sense, ''Precovery'' (published in 2008, aiming to search all known NEAs in few archives via IMCCE's SkyBoT server) and ''Mega-Precovery'' (published in 2010, querying the IMCCE's Miriade server) were made available to the community via the EURONEAR website (euronear.imcce.fr). Briefly, Mega-Precovery aims to search one or a few known asteroids or comets in a mega-collection including millions of images from some of the largest observatory archives: ESO (15 instruments served by ESO Archive including VLT), NVO (8 instruments served by U.S. NVO Archive), CADC (11 instruments, including HST and Gemini), plus other important instrument archives: SDSS, CFHTLS, INT-WFC, Subaru-SuprimeCam and AAT-WFI, adding together 39 instruments and 4.3 million images (Mar 2014), and our Mega-Archive is growing. Here we present some of the most important results obtained with our data-mining software and some new planned search options of Mega-Precovery. Particularly, the following capabilities will be added soon: the ING archive (all imaging cameras) will be included and new search options will be made available (such as query by orbital elements and by observations) to be able to target new Solar System objects such as Virtual Impactors, bolides, planetary satellites, TNOs (besides the comets added recently). In order to better characterize the archives, we introduce the ''AOmegaA'' factor (archival etendue) proportional to the AOmega (etendue) and the number of images in an archive. With the aim to enlarge the Mega-Archive database, we invite the

  7. Thermophysical properties of near-Earth asteroid (341843) 2008 EV5 from WISE data

    CERN Document Server

    Alí-Lagoa, V; Delbo, M; Gundlach, B; Blum, J; Licandro, J

    2013-01-01

    Aims. To derive the thermal inertia of 2008 EV$_5$, the baseline target for the Marco Polo-R mission proposal, and infer information about the size of the particles on its surface. Methods. Values of thermal inertia are obtained by fitting an asteroid thermophysical model to NASA's Wide-field Infrared Survey Explorer (WISE) infrared data. From the constrained thermal inertia and a model of heat conductivity that accounts for different values of the packing fraction (a measure of the degree of compaction of the regolith particles), grain size is derived. Results. We obtain an effective diameter $D = 370 \\pm 6\\,\\mathrm{m}$, geometric visible albedo $p_V = 0.13 \\pm 0.05$ (assuming $H=20.0 \\pm 0.4$), and thermal inertia $\\Gamma = 450 \\pm 60$ J/m2/s(1/2)/K at the 1-$\\sigma$ level of significance for its retrograde spin pole solution. The regolith particles radius is $r = 6.6^{+1.3}_{-1.3}$ mm for low degrees of compaction, and $r = 12.5^{+2.7}_{-2.6}$ mm for the highest packing densities.

  8. Formation of the wide asynchronous binary asteroid population

    Energy Technology Data Exchange (ETDEWEB)

    Jacobson, Seth A. [Department of Astrophysical and Planetary Science, UCB 391, University of Colorado, Boulder, CO 80309 (United States); Scheeres, Daniel J.; McMahon, Jay [Department of Aerospace Engineering Sciences, UCB 429, University of Colorado, Boulder, CO 80309 (United States)

    2014-01-01

    We propose and analyze a new mechanism for the formation of the wide asynchronous binary population. These binary asteroids have wide semimajor axes relative to most near-Earth and main belt asteroid systems. Confirmed members have rapidly rotating primaries and satellites that are not tidally locked. Previously suggested formation mechanisms from impact ejecta, from planetary flybys, and directly from rotational fission events cannot satisfy all of the observations. The newly hypothesized mechanism works as follows: (1) these systems are formed from rotational fission, (2) their satellites are tidally locked, (3) their orbits are expanded by the binary Yarkovsky-O'Keefe-Radzievskii-Paddack (BYORP) effect, (4) their satellites desynchronize as a result of the adiabatic invariance between the libration of the secondary and the mutual orbit, and (5) the secondary avoids resynchronization because of the YORP effect. This seemingly complex chain of events is a natural pathway for binaries with satellites that have particular shapes, which define the BYORP effect torque that acts on the system. After detailing the theory, we analyze each of the wide asynchronous binary members and candidates to assess their most likely formation mechanism. Finally, we suggest possible future observations to check and constrain our hypothesis.

  9. Small Near-Earth Asteroids in the Palomar Transient Factory Survey: A Real-Time Streak-detection System

    Science.gov (United States)

    Waszczak, Adam; Prince, Thomas A.; Laher, Russ; Masci, Frank; Bue, Brian; Rebbapragada, Umaa; Barlow, Tom; Surace, Jason; Helou, George; Kulkarni, Shrinivas

    2017-03-01

    Near-Earth asteroids (NEAs) in the 1–100 meter size range are estimated to be ∼1,000 times more numerous than the ∼15,000 currently cataloged NEAs, most of which are in the 0.5–10 kilometer size range. Impacts from 10–100 meter size NEAs are not statistically life-threatening, but may cause significant regional damage, while 1–10 meter size NEAs with low velocities relative to Earth are compelling targets for space missions. We describe the implementation and initial results of a real-time NEA-discovery system specialized for the detection of small, high angular rate (visually streaked) NEAs in Palomar Transient Factory (PTF) images. PTF is a 1.2-m aperture, 7.3 deg2 field of view (FOV) optical survey designed primarily for the discovery of extragalactic transients (e.g., supernovae) in 60-second exposures reaching ∼20.5 visual magnitude. Our real-time NEA discovery pipeline uses a machine-learned classifier to filter a large number of false-positive streak detections, permitting a human scanner to efficiently and remotely identify real asteroid streaks during the night. Upon recognition of a streaked NEA detection (typically within an hour of the discovery exposure), the scanner triggers follow-up with the same telescope and posts the observations to the Minor Planet Center for worldwide confirmation. We describe our 11 initial confirmed discoveries, all small NEAs that passed 0.3–15 lunar distances from Earth. Lastly, we derive useful scaling laws for comparing streaked-NEA-detection capabilities of different surveys as a function of their hardware and survey-pattern characteristics. This work most directly informs estimates of the streak-detection capabilities of the Zwicky Transient Facility (ZTF, planned to succeed PTF in 2017), which will apply PTF’s current resolution and sensitivity over a 47-deg2 FOV.

  10. Spectral and rotational properties of near-Earth asteroid (162173) Ryugu, target of the Hayabusa2 sample return mission

    Science.gov (United States)

    Perna, D.; Barucci, M. A.; Ishiguro, M.; Alvarez-Candal, A.; Kuroda, D.; Yoshikawa, M.; Kim, M.-J.; Fornasier, S.; Hasegawa, S.; Roh, D.-G.; Müller, T. G.; Kim, Y.

    2017-02-01

    Context. The JAXA Hayabusa2 mission will perform the first ever sample return from a primitive asteroid. The target near-Earth asteroid (162173) Ryugu will be reached in mid-2018 and its samples will be returned to the Earth by the end of 2020. Aims: We want to improve the current knowledge of the compositional and rotational properties of Ryugu, which are still presenting some uncertainties that might affect the mission operations and scientific return. Methods: We acquired high-quality photometric time-series data with the FORS2 instrument at the Very Large Telescope of the European Southern Observatory (ESO-VLT, Chile). We also acquired four FORS2 visible spectra and three X-shooter spectra in the 0.35-2.15 μm range, at different rotational phases. Results: We obtained the currently highest-quality visual light-curve of Ryugu. A best solution of 7.63 h is found for the rotational period, while a short-period solution (i.e., P ≈ 3.8 h) is ruled out by the clearly non-symmetric light-curve. The obtained spectra are generally similar and featureless, but present a drop-off of the reflectance at team for the mission preparation and implementation, improving our knowledge of Ryugu's spin properties. Our new spectra constrain the compositional and geological context of the Ryugu's surface in order to prepare the planning of mission observations and support the working group for the selection of possible landing and sampling sites. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programme 097.C-0248.

  11. Alternate Science Investigations for the Kepler Spacecraft: Precision Rotation Periods and Shapes of Near-Earth Asteroids

    CERN Document Server

    Elvis, Martin; Williams, Gareth V

    2013-01-01

    We propose to use a modest fraction of the re-purposed Kepler mission time and apertures to greatly increase the quantity and quality of our knowledge of near-Earth asteroids (NEAs) rotation and shape. NEAs are important for understanding the origins of the Solar System, for selecting targets for robotic and human visits, and for hazardous object deflection. While NEAs are being discovered at a rate of 1000/year, only a ~75/year have well-measured rotation periods and shapes. Not only can the Kepler mission greatly increase the numbers of well-determined NEA rotation periods (to >1000 in 5 years), but may do so with order-of-magnitude greater precision than is routinely achieved from the ground. This will enable 3-D tomographic maps to be produced for the ~250 of the brighter NEAs. A multi-year science program would enable improved data quality checks, larger samples and additional types of science. All these numbers are preliminary. We list a number of issues to be resolved before this program can be properl...

  12. Small near-Earth asteroids in the Palomar Transient Factory survey: A real-time streak-detection system

    CERN Document Server

    Waszczak, Adam; Laher, Russ; Masci, Frank; Bue, Brian; Rebbapragada, Umaa; Barlow, Tom; Surace, Jason; Helou, George; Kulkarni, Shrinivas

    2016-01-01

    Near-Earth asteroids (NEAs) in the 1-100 meter size range are estimated to be $\\sim$1,000 times more numerous than the $\\sim$15,000 currently-catalogued NEAs, most of which are in the 0.5-10 kilometer size range. Impacts from 10-100 meter size NEAs are not statistically life-threatening but may cause significant regional damage, while 1-10 meter size NEAs with low velocities relative to Earth are compelling targets for space missions. We describe the implementation and initial results of a real-time NEA-discovery system specialized for the detection of small, high angular rate (visually-streaked) NEAs in Palomar Transient Factory (PTF) images. PTF is a 1.2-m aperture, 7.3-deg$^2$ field-of-view optical survey designed primarily for the discovery of extragalactic transients (e.g., supernovae) in 60-second exposures reaching $\\sim$20.5 visual magnitude. Our real-time NEA discovery pipeline uses a machine-learned classifier to filter a large number of false-positive streak detections, permitting a human scanner t...

  13. Rotationally Resolved Photometry of the V-type Near-Earth Asteroid 4055 Magellan (1985 DO2)

    Science.gov (United States)

    Garcia, Karen; Truong, T.; Hicks, M. D.; Barajas, T.; Foster, J.

    2011-05-01

    The Near-Earth Asteroid (NEA) 4055 Magellan was discovered by Glo Helin at Palomar Mountain (IAUC 4638) and was one of the first known minor planets with surface reflectance properties comparable to that of 4 Vesta (Tholen, 1988). Broad-band photometry and near-IR spectroscopy revealed strong 0.9 and 1.9 micron proxene bands, suggesting a compositional similarity of 4055 Magellan with that of 4 Vesta and the basaltic achondrite meteorites (Cruikshank et al. 1991). In anticipation of the Dawn mission to 4 Vesta we obtained 5 partial nights, 2010 August 9/10/12/13/14, of Bessel R photometry of 4055 Magellan at the Jet Propulsion Laboratory Table Mountain 0.6-m telescope (TMO). We measured a synodic period of 7.488+/-0.001 hr, similar to the 7.475+-0.001 hr period obtained by Pravec et al. (http://www.asu.cas.cz/ ppravec/newres.txt). Our object exhibited a large lightcurve amplitude (delta_M 0.8 mag) implying a highly elongated shape. We used our TMO photometry and the absolute magnitude as tabulated by the Minor Planet Center to construct a rudimentary solar phase curve. We derived a phase parameter g=0.30, similar to the phase behavior as measured by Pravec and colleagues (http://www.asu.cas.cz/ ppravec/neo.html). Our high g implies a shallow solar phase slope, consistent with the object's high albeldo (rho=0.31) obtained from thermal measurements (Delbo et al. 2003). The photometric properties of the V-type 4055 Magellan , such as shallow phase slope and high albedo, are consistent with 4 Vesta, giving us confidence in using NEA vestoids as photometric analogs for 4 Vesta.

  14. The Use of the Integrated Medical Model for Forecasting and Mitigating Medical Risks for a Near-Earth Asteroid Mission

    Science.gov (United States)

    Kerstman, Eric; Saile, Lynn; Freire de Carvalho, Mary; Myers, Jerry; Walton, Marlei; Butler, Douglas; Lopez, Vilma

    2011-01-01

    Introduction The Integrated Medical Model (IMM) is a decision support tool that is useful to space flight mission managers and medical system designers in assessing risks and optimizing medical systems. The IMM employs an evidence-based, probabilistic risk assessment (PRA) approach within the operational constraints of space flight. Methods Stochastic computational methods are used to forecast probability distributions of medical events, crew health metrics, medical resource utilization, and probability estimates of medical evacuation and loss of crew life. The IMM can also optimize medical kits within the constraints of mass and volume for specified missions. The IMM was used to forecast medical evacuation and loss of crew life probabilities, as well as crew health metrics for a near-earth asteroid (NEA) mission. An optimized medical kit for this mission was proposed based on the IMM simulation. Discussion The IMM can provide information to the space program regarding medical risks, including crew medical impairment, medical evacuation and loss of crew life. This information is valuable to mission managers and the space medicine community in assessing risk and developing mitigation strategies. Exploration missions such as NEA missions will have significant mass and volume constraints applied to the medical system. Appropriate allocation of medical resources will be critical to mission success. The IMM capability of optimizing medical systems based on specific crew and mission profiles will be advantageous to medical system designers. Conclusion The IMM is a decision support tool that can provide estimates of the impact of medical events on human space flight missions, such as crew impairment, evacuation, and loss of crew life. It can be used to support the development of mitigation strategies and to propose optimized medical systems for specified space flight missions. Learning Objectives The audience will learn how an evidence-based decision support tool can be

  15. Physical Characterization of the Binary Asteroid 66146 (1998 Tu3)

    Science.gov (United States)

    Truong, Thien-Tin; Hicks, M.; Mayes, D.; Barajas, T.; Garcia, K.

    2011-01-01

    The near-Earth asteroid 66146 (1998 TU3) was discovered on 1998 October 13 by the LINEAR NEO survey (MPEC 1998-U03). We obtained five nights of Bessel BVRI observations (2010 Aug 6,7,10,12,13 UT) and one night of Bessel R (August 8 PST) at the JPL Table Mountain Observatory (TMO) 0.6-m telescope near Wrightwood, California. These observations were obtained as part of our ongoing survey at TMO of Potentially Hazardous Asteroids (PHAs), planetary radar targets, and low delta-V near-Earth asteroids (NEOs). The object's rotationally averaged colors (B-R=1.238+/-0.011 mag; V-R=0.440+/-0.008 mag; R-I=0.275+/-0.010 mag) were found most compatible with an Sk-type spectral classification (Bus Taxonomy)/S-type (Tholen Taxonomy). This association was obtained through a comparison of our colors with the 1341 asteroid spectra in the SMASS II database (Bus & Binzel 2002). Our classification differs significantly from the Q-type taxonomy reported by Whitely (2002). Assuming a solar phase parameter g=0.15 we performed a period search using standard Fourier techniques. We found a best-fit rotational period Psyn=2.378+/-0.001 hr, in excellent agreement with the 2.3779+/-0.0004 period determined by Richards et al. (2007). The dispersion in the phased single period lightcurve strongly suggests that 1998 TU3 is be a binary system, with variations in observed flux caused by an unresolved, tidally locked secondary companion. Fitting a 2-period model as described by Pravec et al. (2000), we found that our photometry agrees well with a binary model (P1=2.378+/-0.01 hr, P2=28.28+/-0.05 hr). We have three additional nights scheduled for this object at TMO (Oct 8, 9, 10 2010 UT), extending our solar phase coverage and allowing us to refine our rotational models. 1998 TU3 will experience an exceptional apparition in 2012. This object may be a good candidate for shape/pole modeling via lightcurve inversion, especially if photometry can be obtained from both northern and southern hemispheres. We

  16. Near Earth Objects

    DEFF Research Database (Denmark)

    Wolff, Stefan

    2006-01-01

    , Near Earth Objects: Asteroids and comets following paths that bring them near the Earth. NEOs have collided with the Earth since its formation, some causing local devastation, some causing global climate changes, yet the threat from a collision with a near Earth object has only recently been recognised...... of starlight by the Sun, and therefore directly observe the structure of space-time. This thesis explores several aspects of the observation of NEOs with Gaia, emphasising detection of NEOs and the quality of orbits computed from Gaia observations. The main contribution is the work on motion detection...

  17. The Asteroid Impact Mission (AIM): Studying the geophysics of small binaries, measuring asteroid deflection and studying impact physics

    Science.gov (United States)

    Kueppers, Michael; Michel, Patrick; AIM Team

    2016-10-01

    Binary asteroids and their formation mechanisms are of particular interest for understanding the evolution of the small bodies in the solar system. Also, hazards to Earth from impact of near-Earth asteroids and their mitigation have drawn considerable interest over the last decades.Those subjects are both addressed by ESA's Asteroid Impact mission, which is part of the Asteroid Impact & Deflection Assessment (AIDA) currently under study in collaboration between NASA and ESA. NASA's DART mission will impact a projectile into the minor component of the binary near-Earth asteroid (65803) Didymos in 2022. The basic idea is to demonstrate the effect of the impact on the orbital period of the secondary around the primary. ESA's AIM will monitor the Didymos system for several months around the DART impact time.AIM will be launched in aurumn 2020. It is foreseen to arrive at Didymos in April 2022. The mission takes advantage of a close approach of Didymos to Earth. The next opportunity would arise in 2040 only.AIM will stay near Didymos for approximately 6 months. Most of the time it will be placed on the illuminated side of the system, at distances of approximately 35 km and 10 km. AIM is expected to move away from Didymos for some time around the DART impact.The reference payload for AIM includes two visual imagers, a hyperspectral camera, a lidar, a thermal infrared imager, a monostatic high frequency radar, and a bistatic low frequency radar. In addition, AIM will deploy a small lander on the secondary asteroid, and two cubesats that will be used for additional, more risky investigations close to or on the surface of the asteroid.Major contributions from AIM are expected in the study of the geophysics of small asteroids (including for the first time, radar measurements of an interior structure), the formation of binary asteroids, the momentum enhancement factor from the DART impact (through measuring the mass and the change of orbit of the seondary), and impact physics

  18. OSIRIS-REx A NASA Mission to a Near Earth Asteroid!...and Other Recent Happenings in the Solar System

    Science.gov (United States)

    Moreau, Michael C.

    2015-01-01

    The OSIRIS-REx Mission launches in 2016 Arrives at Asteroid Bennu-2018 Returns a sample to Earth -2023 The mission, OSIRIS-REx, will visit an asteroid and return a sample from the early Solar System to help us understand how our Solar System formed.

  19. Near-Earth asteroid flyby trajectories from the Sun-Earth L2 for Chang'e-2's extended flight

    Science.gov (United States)

    Gao, Yang

    2013-02-01

    Driven by curiosity about possible flight options for the Chang'e-2 spacecraft after it remains at the Sun-Earth L2 point, effective approaches were developed for designing preliminary fuel-optimal near-Earth asteroid flyby trajectories. The approaches include the use of modified unstable manifolds, grid search of the manifolds' parameters, and a two-impulse maneuver for orbital phase matching and z-axis bias change, and are demonstrated to be effective in asteroid target screening and trajectory optimization. Asteroid flybys are expected to be within a distance of 2 × 107 km from the Earth owing to the constrained Earth-spacecraft communication range. In this case, the spacecraft's orbital motion is significantly affected by the gravities of both the Sun and the Earth, and therefore, the concept of the "heliocentric oscillating-Kepler orbit" is proposed, because the classical orbital elements of the flyby trajectories referenced in the heliocentric inertial frame oscillate significantly with respect to time. The analysis and results presented in this study show that, among the asteroids whose orbits are the most accurately predicted, "Toutatis", "2005 NZ6", or "2010 CL19" might be encountered by Chang'e-2 in late 2012 or 2013 with total impulses less than 100m/s.

  20. Near-Earth asteroid flyby trajectories from the Sun-Earth L2 for Chang'e-2's extended flight

    Institute of Scientific and Technical Information of China (English)

    Yang Gao

    2013-01-01

    Driven by curiosity about possible flight options for the Chang'e-2 spacecraft after it remains at the Sun-Earth L2 point,effective approaches were developed for designing preliminary fuel-optimal near-Earth asteroid flyby trajectories.The approaches include the use of modified unstable manifolds,grid search of the manifolds' parameters,and a two-impulse maneuver for orbital phase matching and z-axis bias change,and are demonstrated to be effective in asteroid target screening and trajectory optimization.Asteroid flybys are expected to be within a distance of 2 × 107 km from the Earth owing to the constrained Earth-spacecraft communication range.In this case,the spacecraft's orbital motion is significantly affected by the gravities of both the Sun and the Earth,and therefore,the concept of the“heliocentric oscillating-Kepler orbit” is proposed,because the classical orbital elements of the flyby trajectories referenced in the heliocentric inertial frame oscillate significantly with respect to time.The analysis and results presented in this study show that,among the asteroids whose orbits are the most accurately predicted,“Toutatis”,“2005 NZ6”,or “2010CL19” might be encountered by Chang'e-2 in late 2012 or 2013 with total impulses less than 100 m/s.

  1. Revisit of Dynamical Mechanisms of Transporting Asteroids in the 3:1 Resonance to the Near-Earth Space

    Institute of Scientific and Technical Information of China (English)

    Jiang-Hui Ji; Lin Liu

    2007-01-01

    It is well-known that the asteroids in the main belt trapped in the 3:1 Mean Motion Resonance (MMR) with Jupiter (at semi-major axes ~2.5 AU) are few in number, forming one of the so-called Kirkwood Gaps. Wisdom pointed out that chaotic motion of such asteroids can increase their eccentricities and make them approach and cross the orbit of Mars (or even the Earth). We numerically investigated the orbital evolution of the asteroids involved in 3:1 MMR (NEOs) over millions of years and revisited the dynamical mechanisms of trasporitng such asteroids into the NEO region. The results show that the dynamical evolution of the asteroids around 2.5 AU is mainly dominated by the 3:1 resonance, the υ5 and υ6 secular resonances and the Kozai resonance, and these bodies can evolve into NEOs through several of the dynamical mechanisms, so indicating possible dynamical origin of the NEOs.

  2. Goldstone radar evidence for short-axis mode non-principal-axis rotation of near-Earth asteroid (214869) 2007 PA8

    Science.gov (United States)

    Brozović, Marina; Benner, Lance A. M.; Magri, Christopher; Scheeres, Daniel J.; Busch, Michael W.; Giorgini, Jon D.; Nolan, Michael C.; Jao, Joseph S.; Lee, Clement G.; Snedeker, Lawrence G.; Silva, Marc A.; Lawrence, Kenneth J.; Slade, Martin A.; Hicks, Michael D.; Howell, Ellen S.; Taylor, Patrick A.; Sanchez, Juan A.; Reddy, Vishnu; Dykhuis, Melissa; Corre, Lucille Le

    2017-04-01

    We report radar and optical photometric observations of near-Earth asteroid (214869) 2007 PA8 obtained during October 2-November 13, 2012. We observed 2007 PA8 on sixteen days with Goldstone (8560 MHz, 3.5 cm) and on five days with the 0.6 m telescope at Table Mountain Observatory. Closest approach was on November 5 at a distance of 0.043 au. Images obtained with Goldstone's new chirp system achieved range resolutions as fine as 3.75 m, placing thousands of pixels on the asteroid's surface, and revealing that 2007 PA8 is an elongated, asymmetric object. Surface features include angularities, facets, and a concavity approximately 400 m in diameter. We used the Shape software to estimate the asteroid's 3D shape and spin state. 2007 PA8 has a broad, rounded end and a tapered, angular end with sharp-crested ridges. The asteroid's effective diameter is 1.35 ± 0.07 km, which in combination with the absolute magnitude of 16.30 ± 0.52 gives an optical albedo of pV = 0.29 ± 0.14. The shape modeling of the radar data revealed that 2007 PA8 is a non-principal axis (NPA) rotator in the short-axis mode with an average period of precession by the long axis around the angular momentum vector of 4.26 ± 0.02 days and an oscillatory period around the long axis of 20.55 ± 3.75 days. The amplitude of rolling around the long axis is 42 ± 7° . The angular momentum vector points toward ecliptic longitude and latitude of 273.6 ± 10°, +16.9 ± 5°. 2007 PA8 is only the second confirmed short-axis mode NPA rotator known in the near-Earth asteroid population after (99942) Apophis (Pravec et al., 2014). 2007 PA8 has a geopotential high at the equator, where the equator is defined as the plane that contains the long and intermediate axis. This geopotential extreme could be interpreted as a large, hidden surface depression, or as evidence that 2007 PA8 is a multi-component body.

  3. The small binary asteroid (939) Isberga

    CERN Document Server

    Carry, B; Scheirich, P; Pravec, P; Molnar, L; Mottola, S; Carbognani, A; Jehin, E; Marciniak, A; Binzel, R P; DeMeo, F E; Birlan, M; Delbo, M; Barbotin, E; Behrend, R; Bonnardeau, M; Colas, F; Farissier, P; Fauvaud, M; Fauvaud, S; Gillier, C; Gillon, M; Hellmich, S; Hirsch, R; Leroy, A; Manfroid, J; Montier, J; Morelle, E; Richard, F; Sobkowiak, K; Strajnic, J; Vachier, F

    2014-01-01

    In understanding the composition and internal structure of asteroids, their density is perhaps the most diagnostic quantity. We aim here to characterize the surface composition, mutual orbit, size, mass, and density of the small main-belt binary asteroid (939) Isberga. For that, we conduct a suite of multi-technique observations, including optical lightcurves over many epochs, near-infrared spectroscopy, and interferometry in the thermal infrared. We develop a simple geometric model of binary systems to analyze the interferometric data in combination with the results of the lightcurve modeling. From spectroscopy, we classify Ibserga as a Sq-type asteroid, consistent with the albedo of 0.14$^{+0.09}_{-0.06}$ (all uncertainties are reported as 3-$\\sigma$ range) we determine (average albedo of S-types is 0.197 $\\pm$ 0.153, Pravec et al., 2012, Icarus 221, 365-387). Lightcurve analysis reveals that the mutual orbit has a period of 26.6304 $\\pm$ 0.0001 h, is close to circular, and has pole coordinates within 7 deg...

  4. Is 1220 Crocus a precessing, binary asteroid?

    Science.gov (United States)

    Binzel, R. P.

    1985-01-01

    Photoelectric data of the asteroid 1220 Crocus over a 13 night period in 1984 revealed the presence of two separate periods. The light curves were indicative of a precessing body, but not one in free precession due to motions induced by a collision. Closer examinations revealed periods of 30.7 and 7.9 hr with amplitudes of 0.87 and 0.15 mag, respectively. An analysis of the source of an external torque which could be causing a forced precession led to the hypothesis that 1220 Crocus has a satellite. Verification of the binary asteroid configuration will depend on more detailed light curves, the possible modulation of the shorter period by the longer, and possible use of the Space Telescope.

  5. Is 1220 Crocus a precessing, binary asteroid?

    Science.gov (United States)

    Binzel, R. P.

    1985-07-01

    Photoelectric data of the asteroid 1220 Crocus over a 13 night period in 1984 revealed the presence of two separate periods. The light curves were indicative of a precessing body, but not one in free precession due to motions induced by a collision. Closer examinations revealed periods of 30.7 and 7.9 hr with amplitudes of 0.87 and 0.15 mag, respectively. An analysis of the source of an external torque which could be causing a forced precession led to the hypothesis that 1220 Crocus has a satellite. Verification of the binary asteroid configuration will depend on more detailed light curves, the possible modulation of the shorter period by the longer, and possible use of the Space Telescope.

  6. PF131010 Ciechanow fireball - the body possible related to Near Earth Asteroids 2010 TB54 and 2010 SX11

    CERN Document Server

    Olech, A; Wisniewski, M; Rudawska, R; Laskowski, J; Polakowski, K; Maciejewski, M; Krzyzanowski, T; Fajfer, T; Tyminski, Z

    2015-01-01

    On 2010 October 13, the Apollo type 20-meter asteroid 2010 TB54 passed within 6.1 lunar distances from the Earth. On the same date, but 11.4 hours earlier, exactly at 02:52:32 UT, the sky over central Poland was illuminated by -8.6 magnitude PF131010 Ciechanow fireball. The trajectory and orbit of the fireball was computed using multi-station data of Polish Fireball Network (PFN). The results indicate that the orbit of the meteoroid which caused the PF131010 fireball is similar to the orbit of 2010 TB54 asteroid and both bodies may be related. Moreover, two days before appearance of Ciechanow fireball another small asteroid denoted as 2010 SX11 passed close to the Earth-Moon system. Its orbit is even more similar to the orbit of Ciechanow fireball parent body than in case of 2010 TB54. The PF131010 Ciechanow entered Earth's atmosphere with the velocity of 12.9 +\\- 0.2 km/s and started to shine at height of 82.5 +\\- 0.3 km. Clear deceleration started after first three seconds of flight, and the terminal veloci...

  7. Formation and Evolution of Binary Asteroids

    CERN Document Server

    Walsh, Kevin J

    2015-01-01

    Satellites of asteroids have been discovered in nearly every known small body population, and a remarkable aspect of the known satellites is the diversity of their properties. They tell a story of vast differences in formation and evolution mechanisms that act as a function of size, distance from the Sun, and the properties of their nebular environment at the beginning of Solar System history and their dynamical environment over the next 4.5 Gyr. The mere existence of these systems provides a laboratory to study numerous types of physical processes acting on asteroids and their dynamics provide a valuable probe of their physical properties otherwise possible only with spacecraft. Advances in understanding the formation and evolution of binary systems have been assisted by: 1) the growing catalog of known systems, increasing from 33 to nearly 250 between the Merline et al. (2002) Asteroids III chapter and now, 2) the detailed study and long-term monitoring of individual systems such as 1999 KW4 and 1996 FG3, 3...

  8. Mutual gravitational potential, force, and torque of a homogeneous polyhedron and an extended body: an application to binary asteroids

    Science.gov (United States)

    Shi, Yu; Wang, Yue; Xu, Shijie

    2017-08-01

    Binary systems are quite common within the populations of near-Earth asteroids, main-belt asteroids, and Kuiper belt asteroids. The dynamics of binary systems, which can be modeled as the full two-body problem, is a fundamental problem for their evolution and the design of relevant space missions. This paper proposes a new shape-based model for the mutual gravitational potential of binary asteroids, differing from prior approaches such as inertia integrals, spherical harmonics, or symmetric trace-free tensors. One asteroid is modeled as a homogeneous polyhedron, while the other is modeled as an extended rigid body with arbitrary mass distribution. Since the potential of the polyhedron is precisely described in a closed form, the mutual gravitational potential can be formulated as a volume integral over the extended body. By using Taylor expansion, the mutual potential is then derived in terms of inertia integrals of the extended body, derivatives of the polyhedron's potential, and the relative location and orientation between the two bodies. The gravitational forces and torques acting on the two bodies described in the body-fixed frame of the polyhedron are derived in the form of a second-order expansion. The gravitational model is then used to simulate the evolution of the binary asteroid (66391) 1999 KW4, and compared with previous results in the literature.

  9. Ground-based Radar Detection of Near-Earth Asteroids%近地小行星地基雷达探测研究现状

    Institute of Scientific and Technical Information of China (English)

    张翔; 季江徽

    2014-01-01

    Ground-based radar detection may act as a powerful means to determine the shape and physical properties of the asteroids in our Solar system. By measuring time delay and doppler frequency of the received echoes, radar systems provide information in ranging and radial velocity of the asteroids. Over the past few decades, more than 500 asteroids (mostly near-Earth ob jects) were detected using radar observations. There are two categories of radar detection: (1) The continuous wave detection, which is adopted to determine the roughness of an asteroid’s surface. (2) The delay-Doppler de-tection,which is likely to produce its three-dimensional model, and to define the rotational state. In the delay-Doppler detection, target asteroids are resolved in line-of-sight distance and line-of-sight velocity, providing two-dimensional images with spatial resolution as fine as meter-scale. Besides radar detection, several other techniques would also provide the shape model of the asteroids, among which the lightcurve inverse method is the most popular one to do that. In comparison with other methods, radar observation may have an advantage on spacial resolution. The lightcurves cannot reveal elaborate information on small features, and the intermediate-scale features of the inversed model are only suggestive. By contrast, radar detection produces resolved images. In this review, we present the radar observation technique and the method for recon-structing three-dimensional models of asteroids from radar measurements. In addition, we also provide several examples of asteroid models by radar detection, and then compare them with other observations for the shape reconstruction for the asteroids.%地基雷达探测是研究太阳系中小行星的重要方法。雷达探测主要有两种方式:(1)连续波探测,可得到小行星表面的粗糙度等参数;(2)延迟多普勒探测,用于反演小行星的三维形状模型并确定自转轴状态。与其他探测方法

  10. Grid-Free 2D Plasma Simulations of the Complex Interaction Between the Solar Wind and Small, Near-Earth Asteroids

    Science.gov (United States)

    Zimmerman, M. I.; Farrell, W. M.; Poppe, A. R.

    2014-01-01

    We present results from a new grid-free 2D plasma simulation code applied to a small, unmagnetized body immersed in the streaming solar wind plasma. The body was purposely modeled as an irregular shape in order to examine photoemission and solar wind plasma flow in high detail on the dayside, night-side, terminator and surface-depressed 'pocket' regions. Our objective is to examine the overall morphology of the various plasma interaction regions that form around a small body like a small near-Earth asteroid (NEA). We find that the object obstructs the solar wind flow and creates a trailing wake region downstream, which involves the interplay between surface charging and ambipolar plasma expansion. Photoemission is modeled as a steady outflow of electrons from illuminated portions of the surface, and under direct illumination the surface forms a non-monotonic or ''double-sheath'' electric potential upstream of the body, which is important for understanding trajectories and equilibria of lofted dust grains in the presence of a complex asteroid geometry. The largest electric fields are found at the terminators, where ambipolar plasma expansion in the body-sized night-side wake merges seamlessly with the thin photoelectric sheath on the dayside. The pocket regions are found to be especially complex, with nearby sunlit regions of positive potential electrically connected to unlit negative potentials and forming adjacent natural electric dipoles. For objects near the surface, we find electrical dissipation times (through collection of local environmental solar wind currents) that vary over at least 5 orders of magnitude: from 39 Micro(s) inside the near-surface photoelectron cloud under direct sunlight to less than 1 s inside the particle-depleted night-side wake and shadowed pocket regions

  11. Asteroid fission, binaries and the small main belt population

    Science.gov (United States)

    Rossi, A.; Jacobson, S.; Marzari, F.; Scheeres, D.

    2011-10-01

    Using a Monte Carlo method we model the spin evolution of small Main Belt asteroids under the joint effects of YORP and collisions. Our simulations allow us to estimate the fraction of asteroids undergoing rotational fission in different size ranges. When an asteroid reaches its disruption spin limit we determine the outcome of its subsequent evolution based on accumulated statistics on their evolution based on numerical integrations (i.e., binary or ternary formation, binary disruption, etc..). Our aim is to predict the percentage of binary asteroids and their properties in the Belt, the number of objects like P/2010 A2 per year and the effects of YORP-induced fission on the overall asteroid size distribution at the small size end.

  12. Binary asteroid population. 3. Secondary rotations and elongations

    Science.gov (United States)

    Pravec, P.; Scheirich, P.; Kušnirák, P.; Hornoch, K.; Galád, A.; Naidu, S. P.; Pray, D. P.; Világi, J.; Gajdoš, Š.; Kornoš, L.; Krugly, Yu. N.; Cooney, W. R.; Gross, J.; Terrell, D.; Gaftonyuk, N.; Pollock, J.; Husárik, M.; Chiorny, V.; Stephens, R. D.; Durkee, R.; Reddy, V.; Dyvig, R.; Vraštil, J.; Žižka, J.; Mottola, S.; Hellmich, S.; Oey, J.; Benishek, V.; Kryszczyńska, A.; Higgins, D.; Ries, J.; Marchis, F.; Baek, M.; Macomber, B.; Inasaridze, R.; Kvaratskhelia, O.; Ayvazian, V.; Rumyantsev, V.; Masi, G.; Colas, F.; Lecacheux, J.; Montaigut, R.; Leroy, A.; Brown, P.; Krzeminski, Z.; Molotov, I.; Reichart, D.; Haislip, J.; LaCluyze, A.

    2016-03-01

    We collected data on rotations and elongations of 46 secondaries of binary and triple systems among near-Earth, Mars-crossing and small main belt asteroids. 24 were found or are strongly suspected to be synchronous (in 1:1 spin-orbit resonance), and the other 22, generally on more distant and/or eccentric orbits, were found or are suggested to have asynchronous rotations. For 18 of the synchronous secondaries, we constrained their librational angles, finding that their long axes pointed to within 20° of the primary on most epochs. The observed anti-correlation of secondary synchroneity with orbital eccentricity and the limited librational angles agree with the theories by Ćuk and Nesvorný (Ćuk, M., Nesvorný, D. [2010]. Icarus 207, 732-743) and Naidu and Margot (Naidu, S.P., Margot, J.-L. [2015]. Astron. J. 149, 80). A reason for the asynchronous secondaries being on wider orbits than synchronous ones may be longer tidal circularization time scales at larger semi-major axes. The asynchronous secondaries show relatively fast spins; their rotation periods are typically VH, the secondary rotations are single-periodic with no signs of chaotic rotation and their periods are constant on timescales from weeks to years. The secondary equatorial elongations show an upper limit of a2 /b2 ∼ 1.5 . The lack of synchronous secondaries with greater elongations appears consistent, considering uncertainties of the axis ratio estimates, with the theory by Ćuk and Nesvorný that predicts large regions of chaotic rotation in the phase space for a2 /b2 ≳√{ 2 } . Alternatively, secondaries may not form or stay very elongated in gravitational (tidal) field of the primary. It could be due to the secondary fission mechanism suggested by Jacobson and Scheeres (Jacobson, S.A., Scheeres, D.J. [2011]. Icarus 214, 161-178), as its efficiency is correlated with the secondary elongation. Sharma (Sharma, I. [2014]. Icarus 229, 278-294) found that rubble-pile satellites with a2 /b2 ≲ 1

  13. Trajectory exploration within asynchronous binary asteroid systems using refined Lagrangian coherent structures

    Science.gov (United States)

    Shang, Haibin; Wu, Xiaoyu; Cui, Pingyuan

    2017-02-01

    Ground observations have found that asynchronous systems constitute most of the population of the near-Earth binary asteroids. This paper concerns the trajectory of a particle in the asynchronous system which is systematically described using periodic ellipsoidal and spherical body models. Due to the non-autonomous characteristics of the asynchronous system, Lagrangian coherent structures (LCS) are employed to identify the various dynamical behaviors. To enhance the accuracy of LCS, a robust LCS finding algorithm is developed incorporating hierarchical grid refinement, one-dimensional search and variational theory verification. In this way, the intricate dynamical transport boundaries are detected efficiently. These boundaries indicate that a total of 15 types of trajectories exist near asynchronous binary asteroids. According to their Kepler energy variations, these trajectories can be grouped into four basic categories, i.e., transitory, escape, impact and flyby trajectories. Furthermore, the influence of the ellipsoid's spin period on the dynamical behavior is discussed in the context of the change of dynamical regions. We found that the transitory and impact motions occur easily in the synchronous-like binary systems, in which the rotation period of the ellipsoid is nearly equal to that of the mutual orbit. Meanwhile, the results confirm a positive correlation between the spinning rate of the ellipsoid and the probability of the escape and flyby trajectories. The LCS also reveal a marked increase in trajectory diversity after a larger initial energy is selected.

  14. The Asteroid Redirect Mission (ARM): Exploration of a Former Binary NEA?

    Science.gov (United States)

    Abell, P. A.; Mazanek, D. D.; Reeves, D. M.; Chodas, P. W.; Gates, M. M.; Johnson, L. N.; Ticker, R. L.

    2016-01-01

    The National Aeronautics and Space Administration (NASA) is developing the Asteroid Redirect Mission (ARM) as a capability demonstration for future human exploration, including use of high-power solar electric propulsion, which allows for the efficient movement of large masses through deep space. The ARM will also demonstrate the capability to conduct proximity operations with natural space objects and crewed operations beyond the security of quick Earth return. The Asteroid Redirect Robotic Mission (ARRM), currently in formulation, will visit a large near-Earth asteroid (NEA), collect a multi-ton boulder from its surface, conduct a demonstration of a slow push planetary defense technique, and redirect the multi-ton boulder into a stable orbit around the Moon. Once returned to cislunar space in the mid-2020s, astronauts aboard an Orion spacecraft will dock with the robotic vehicle to explore the boulder and return samples to Earth. The ARM is part of NASA's plan to advance technologies, capabilities, and spaceflight experience needed for a human mission to the Martian system in the 2030s. The ARM and subsequent availability of the asteroidal material in cis-lunar space, provide significant opportunities to advance our knowledge of small bodies in the synergistic areas of science, planetary defense, and in-situ resource utilization (ISRU). The current reference target for the ARM is NEA (341843) 2008 EV5, which may have been the primary body of a former binary system (Busch et al., 2011; Tardivel et al., 2016). The ARRM will perform several close proximity operations to investigate the NEA and map its surface. A detailed investigation of this object may allow a better understanding of binary NEA physical characteristics and the possible outcomes for their evolution. An overview of the ARM robotic and crewed segments, including mission operations, and a discussion of potential opportunities for participation with the ARM will be provided in this presentation.

  15. 利用修正高斯模型分析Q型近地小行星表面矿物光谱特征∗%Analysis of Q-type Near-Earth Asteroid Spectra with Modified Gaussian Model

    Institute of Scientific and Technical Information of China (English)

    王昊; 马月华; 赵海斌; 卢晓平

    2016-01-01

    Using the Modified Gaussian Model (MGM) method developed by Sun-shine et al. to extract mineralogical information from the spectra of eight Q-type near-earth asteroids, we obtain their surface composition of orthopyroxene and clinopy-roxene. We further get a compositional proportion of each asteroid: the abundance of clinopyroxene is about 70% on the suface of asteroids 5143, 7341, 66146, and 162058, and it is about 60%on the surface of asteroids 1862, 4688, and 5660, but only 43%on the surface of asteroid 3753. Then we analyse the reason of apparently low abundance of clinopyroxene on the surface of asteroid 3753. The level of metamorphism experi-enced by the asteroid increases with the decreasing of the distance from the center. So the asteroid 3753 is highly metamorphosed, and the abundance of clinopyroxene is low.%利用Sunshine等人基于实验室标准矿物光谱提出的修正高斯模型(Modified Gaussian Model, MGM),对8颗Q型近地小行星的反射光谱进行分析,得到了所研究的Q型小行星表面主要矿物是斜方辉石和单斜辉石的结论,估算了单斜辉石的丰度,对3753号小行星呈现出的表面单斜辉石丰度很低的现象进行了分析。

  16. Tidal stress and failure in the moon of binary asteroid systems: Application to asteroid (65803) Didymos

    Science.gov (United States)

    Sophal Pou, Laurent; Garcia, Raphael F.; Mimoun, David; Murdoch, Naomi; Karatekin, Ozgur

    2017-04-01

    Rocky remnants left over from the early formation of the Solar System, asteroids are a target of choice for planetary science since much about the history of planetary formation and small body evolution processes can be learnt by studying them. Here we consider the case of the binary asteroid (65803) Didymos, the target of several mission proposals e.g., AIM [1] and DART [2]. A mission to Didymos would be a great opportunity for in-situ geophysical investigation, providing information on the surface and interior of asteroids. Such studies would improve our knowledge of binary asteroid formation and subsequent evolution of asteroids, thus of the history of the Solar System. As Didymos is a binary asteroid [3] with the main 800-meter diameter asteroid named Didymain and a 150-meter sized moon named Didymoon, both are subject to tidal stress. Recent investigations suggest that Didymoon is tidally locked and moves in a retrograde motion around Didymain along an elliptic orbit with a 0.03 eccentricity at most. In the case of an eccentric orbit, the tidal stress varies periodically and may be strong enough to cause tidal quakes on Didymoon at some points of the orbit. For this study, we modelled Didymoon as a spherical, layered body with different internal structures: a homogeneous model, and two models with a 1-meter and 10-meter regolith layer on top of a stronger internal core. Simulations show that, for a cohesionless body with an internal friction angle of 30°, tidal stress is strong enough to cause failure at the surface of Didymoon. A maximal stress is reached around the poles and for a mean anomaly of 90°. These results would mean that if tidal quakes occur on Didymoon, then they are likely to happen at these locations. An extension of these results to an ellipsoidal model of Didymoon is also presented for comparison with the spherical case and for application to other bodies. [1]: P. Michel et al., Science case for the asteroid impact mission (aim): A

  17. Equilibrium figures of inhomogeneous synchronous binary asteroids

    Science.gov (United States)

    Descamps, P.

    2010-06-01

    The present paper deals with the application of the classical theory of equilibrium figures of two rotating liquid masses to the case where bodies exhibit a radially stratified internal density distribution so that they can be considered as inhomogeneous bodies. The derived ellipsoidal shape solutions are applied to five real systems of equal-sized synchronous asteroids. Furthermore, internal inhomogeneity puts strong constraints on the surface grain density. A satisfactory model fit is achieved with internal densities of asteroids steadily increasing outwards. In particular, from such an approach we derived grain densities of the considered systems in agreement with their mineralogical composition inferred from reflectance spectroscopy. According to this new approach, 4492 Debussy, presently of unknown spectral type, is predicted to appear as a C-type object with a grain density on the order of 2 g/cm 3.

  18. The Evolutionary Outcomes of Expansive Binary Asteroid Systems

    Science.gov (United States)

    McMahon, Jay W.

    2016-10-01

    Singly synchronous binary asteroid systems have several evolutionary end-states, which depend heavily on the BYORP effect. In the case of expansive BYORP, the binary system could evolve to become a wide asynchronous binary system (Jacobson, et al 2014), or the system could expand far enough to become disrupted to form a heliocentric pair (Vokrouhlicky et al 2008). Cuk et al (2011) found that upon expanding the secondary will quickly become asynchronous, and will end up re-establishing synchronous rotation with the opposite attitude, causing the binary orbit to subsequently contract. The distinction between these outcomes depends on whether the secondary asteroid stays synchronized, which keeps the BYORP effect active and the orbit expanding. As the orbit expands, the secondary libratation will expand, and the libration will also causes large variations in the binary orbit due to the elongation of the secondary. If the eccentricity and libration are bound to small enough values the system can expand significantly. This work discusses the stability of the libration and orbital motion as a binary expands from a wide variety of simulation runs with various parameters. We investigate how the strength of tides and BYORP change the stability of the librational motion; an important factor is the speed of BYORP expansion as slower expansion allows tides to have a more stabilizing effect. We also investigate the effect of heliocentric orbit semimajor axis and eccentricity. We find that resonances between the coupled orbit-libration frequencies and the heliocentric orbit cause instability in the binary orbit eccentricity which produces a strong preference for wide binary production, especially amongst retrograde binary systems. This instability also becomes stronger with large heliocentric eccentricities. Prograde binaries are more stable and can possible grow to become asteroid pairs. We find that even in the presence of tides, reestablishment of synchronous spin into a

  19. Ejecta Cloud from a Kinetic Impact on the Secondary of a Binary Asteroid: I. Mechanical Environment and Dynamic Model

    CERN Document Server

    Yu, Yang; Schwartz, Stephen R; Naidu, Shantanu P; Benner, Lance A M

    2016-01-01

    An understanding of the post-impact dynamics of ejecta clouds are crucial to the planning of a kinetic impact mission to an asteroid, and also has great implications for the history of planetary formation. The purpose of this article to track the evolution of ejecta produced by AIDA mission, which targets for kinetic impact the secondary of near-Earth binary asteroid 65803 Didymos on 2022, and to feedback essential informations to AIDA's ongoing phase-A study. We present a detailed dynamic model for the simulation of an ejecta cloud from a binary asteroid that synthesizes all relevant forces based on a previous analysis of the mechanical environment. We apply our method to gain insight into the expected response of Didymos to the AIDA impact, including the subsequent evolution of debris and dust. The crater scaling relations from laboratory experiments are employed to approximate the distributions of ejecta mass and launching speed. The size composition of fragments is modeled with a power law fitted from obs...

  20. Rotation Periods of Binary Asteroids with Large Separations - Confronting the Escaping Ejecta Binaries Model with Observations

    CERN Document Server

    Polishook, D; Prialnik, D

    2010-01-01

    Durda et al. (2004), using numerical models, suggested that binary asteroids with large separation, called Escaping Ejecta Binaries (EEBs), can be created by fragments ejected from a disruptive impact event. It is thought that six binary asteroids recently discovered might be EEBs because of the high separation between their components (~100 > a/Rp > ~20). However, the rotation periods of four out of the six objects measured by our group and others and presented here show that these suspected EEBs have fast rotation rates of 2.5 to 4 hours. Because of the small size of the components of these binary asteroids, linked with this fast spinning, we conclude that the rotational-fission mechanism, which is a result of the thermal YORP effect, is the most likely formation scenario. Moreover, scaling the YORP effect for these objects shows that its timescale is shorter than the estimated ages of the three relevant Hirayama families hosting these binary asteroids. Therefore, only the largest (D~19 km) suspected astero...

  1. Mapping Near-Earth Hazards

    Science.gov (United States)

    Kohler, Susanna

    2016-06-01

    How can we hunt down all the near-Earth asteroids that are capable of posing a threat to us? A new study looks at whether the upcoming Large Synoptic Survey Telescope (LSST) is up to the job.Charting Nearby ThreatsLSST is an 8.4-m wide-survey telescope currently being built in Chile. When it goes online in 2022, it will spend the next ten years surveying our sky, mapping tens of billions of stars and galaxies, searching for signatures of dark energy and dark matter, and hunting for transient optical events like novae and supernovae. But in its scanning, LSST will also be looking for asteroids that approach near Earth.Cumulative number of near-Earth asteroids discovered over time, as of June 16, 2016. [NASA/JPL/Chamberlin]Near-Earth objects (NEOs) have the potential to be hazardous if they cross Earths path and are large enough to do significant damage when they impact Earth. Earths history is riddled with dangerous asteroid encounters, including the recent Chelyabinsk airburst in 2013, the encounter that caused the kilometer-sized Meteor Crater in Arizona, and the impact thought to contribute to the extinction of the dinosaurs.Recognizing the potential danger that NEOs can pose to Earth, Congress has tasked NASA with tracking down 90% of NEOs larger than 140 meters in diameter. With our current survey capabilities, we believe weve discovered roughly 25% of these NEOs thus far. Now a new study led by Tommy Grav (Planetary Science Institute) examines whether LSST will be able to complete this task.Absolute magnitude, H, of asynthetic NEO population. Though these NEOs are all larger than 140 m, they have a large spread in albedos. [Grav et al. 2016]Can LSST Help?Based on previous observations of NEOs and resulting predictions for NEO properties and orbits, Grav and collaborators simulate a synthetic population of NEOs all above 140 m in size. With these improved population models, they demonstrate that the common tactic of using an asteroids absolute magnitude as a

  2. Dynamics of rotationally fissioned asteroids: Source of observed small asteroid systems

    CERN Document Server

    Jacobson, Seth A

    2014-01-01

    We present a model of near-Earth asteroid (NEA) rotational fission and ensuing dynamics that describes the creation of synchronous binaries and all other observed NEA systems including: doubly synchronous binaries, high- e binaries, ternary systems, and contact binaries. Our model only presupposes the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect, "rubble pile" asteroid geophysics, and gravitational interactions. The YORP effect torques a "rubble pile" asteroid until the asteroid reaches its fission spin limit and the components enter orbit about each other (Scheeres, D.J. [2007]. Icarus 189, 370-385). Non-spherical gravitational potentials couple the spin states to the orbit state and chaotically drive the system towards the observed asteroid classes along two evolutionary tracks primarily distinguished by mass ratio. Related to this is a new binary process termed secondary fission - the secondary asteroid of the binary system is rotationally accelerated via gravitational torques until it fissions, thu...

  3. Rotation periods of binary asteroids with large separations - Confronting the Escaping Ejecta Binaries model with observations

    Science.gov (United States)

    Polishook, D.; Brosch, N.; Prialnik, D.

    2011-03-01

    Durda et al. (Durda, D.D., Bottke, W.F., Enke, B.L., Merline, W.J., Asphaug, E., Richardson, D.C., Leinhardt, Z.M. [2004]. Icarus 170, 243-257), using numerical models, suggested that binary asteroids with large separation, called Escaping Ejecta Binaries (EEBs), can be created by fragments ejected from a disruptive impact event. It is thought that six binary asteroids recently discovered might be EEBs because of the high separation between their components (∼100 > a/Rp > ∼20). However, the rotation periods of four out of the six objects measured by our group and others and presented here show that these suspected EEBs have fast rotation rates of 2.5-4 h. Because of the small size of the components of these binary asteroids, linked with this fast spinning, we conclude that the rotational-fission mechanism, which is a result of the thermal YORP effect, is the most likely formation scenario. Moreover, scaling the YORP effect for these objects shows that its timescale is shorter than the estimated ages of the three relevant Hirayama families hosting these binary asteroids. Therefore, only the largest (D ∼ 19 km) suspected asteroid, (317) Roxane, could be, in fact, the only known EEB. In addition, our results confirm the triple nature of (3749) Balam by measuring mutual events on its lightcurve that match the orbital period of a nearby satellite in addition to its distant companion. Measurements of (1509) Esclangona at different apparitions show a unique shape of the lightcurve that might be explained by color variations.

  4. An investigation of the low-DeltaV near-Earth asteroids (341843) 2008 EV5 and (52381) 1993 HA. Two suitable targets for the ARM and MarcoPolo-M5 space missions

    CERN Document Server

    Perna, D; Monteiro, F; Lantz, C; Lazzaro, D; Merlin, F

    2016-01-01

    The Asteroid Redirect Mission (ARM) under development by NASA is being planned to collect a multi-meter boulder from a near-Earth asteroid (NEA), and to bring it to the cis-lunar space in the mid-2020's for future study and exploitation by a crewed mission. The MarcoPolo-M5 project is being proposed in 2016 for the M5 mission opportunity by ESA, to bring back to Earth a sample from a very primitive D-type NEA. We aim to further characterize the physical properties of two optimal targets for sample return space missions, the low-DeltaV NEAs (341843) 2008 EV5 and (52381) 1993 HA. 2008 EV5 is the baseline target of ARM, but only one spectrum of this object exists in the literature. 1993 HA is a very favourable target for a space mission based on its dynamical properties: here we intend to assess if it is a suitable target for MarcoPolo-M5. We obtained visible spectroscopy of 2008 EV5 with the FORS2 instrument at ESO-VLT, at different rotational phases. We also obtained visible and near-infrared spectroscopy of 1...

  5. Modeling and analysis of periodic orbits around a contact binary asteroid

    NARCIS (Netherlands)

    Feng, J.; Noomen, R.; Visser, P.N.A.M.; Yuan, J.

    2015-01-01

    The existence and characteristics of periodic orbits (POs) in the vicinity of a contact binary asteroid are investigated with an averaged spherical harmonics model. A contact binary asteroid consists of two components connected to each other, resulting in a highly bifurcated shape. Here, it is repre

  6. Modeling and analysis of periodic orbits around a contact binary asteroid

    NARCIS (Netherlands)

    Feng, J.; Noomen, R.; Visser, P.N.A.M.; Yuan, J.

    2015-01-01

    The existence and characteristics of periodic orbits (POs) in the vicinity of a contact binary asteroid are investigated with an averaged spherical harmonics model. A contact binary asteroid consists of two components connected to each other, resulting in a highly bifurcated shape. Here, it is

  7. Comprehensive Gravity and Dynamics Model Determination of Binary Asteroid Systems

    Science.gov (United States)

    Fahnestock, Eugene G.

    2009-09-01

    I present the development of additional tools within the framework of JPL's in-house Mirage / Orbit Determination Program (ODP) software to allow the determination of a comprehensive gravity and dynamics model for any binary asteroid system potentially visited by a spacecraft rendezvous mission. This involves a concurrent global solution for the gravity fields of both components, sufficient parametric description of their fully-coupled translational and rotational dynamics, the spacecraft state, and all other relevant force model parameters. This estimation process primarily uses spacecraft radio tracking data (range and Doppler measurements), supplemented by in-situ imaging observations data types. A solution for the gravity field (gravity analysis) and a simultaneous solution for the spacecraft motion and other system properties has been performed before using the ODP for solitary irregular small solar system bodies (e.g. Eros, visited by the NEAR mission), but never for any closely gravitationally bound pair of irregular small solar system bodies. I am expanding NASA's tool set to allow the latter, in preparation for potential future spacecraft rendezvous missions. This is nontrivial, because of the need to incorporate propagation of the binary system's fully-coupled rigid-body dynamical model either along with the spacecraft state within Mirage/ODP or "offline", followed by interpolating an appropriate "binary dynamics ephemeris” representation. Further, this model optionally incorporates formulations for body gravity fields not previously used in this context, and it can be computationally very expensive. However, successfully performing this model determination at a binary asteroid yields valuable science results concerning internal mass distributions and structures of the components and insight into the system's formation and evolution. In this poster I present my current progress in the development of this capability and results for the quality of science

  8. Dynamics of rotationally fissioned asteroids: Source of observed small asteroid systems

    Science.gov (United States)

    Jacobson, Seth A.; Scheeres, Daniel J.

    2011-07-01

    We present a model of near-Earth asteroid (NEA) rotational fission and ensuing dynamics that describes the creation of synchronous binaries and all other observed NEA systems including: doubly synchronous binaries, high- e binaries, ternary systems, and contact binaries. Our model only presupposes the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect, "rubble pile" asteroid geophysics, and gravitational interactions. The YORP effect torques a "rubble pile" asteroid until the asteroid reaches its fission spin limit and the components enter orbit about each other (Scheeres, D.J. [2007]. Icarus 189, 370-385). Non-spherical gravitational potentials couple the spin states to the orbit state and chaotically drive the system towards the observed asteroid classes along two evolutionary tracks primarily distinguished by mass ratio. Related to this is a new binary process termed secondary fission - the secondary asteroid of the binary system is rotationally accelerated via gravitational torques until it fissions, thus creating a chaotic ternary system. The initially chaotic binary can be stabilized to create a synchronous binary by components of the fissioned secondary asteroid impacting the primary asteroid, solar gravitational perturbations, and mutual body tides. These results emphasize the importance of the initial component size distribution and configuration within the parent asteroid. NEAs may go through multiple binary cycles and many YORP-induced rotational fissions during their approximately 10 Myr lifetime in the inner Solar System. Rotational fission and the ensuing dynamics are responsible for all NEA systems including the most commonly observed synchronous binaries.

  9. Capturing Near Earth Objects

    OpenAIRE

    Baoyin, Hexi; CHEN Yang; Li, Junfeng

    2011-01-01

    Recently, Near Earth Objects (NEOs) have been attracting great attention, and thousands of NEOs have been found to date. This paper examines the NEOs' orbital dynamics using the framework of an accurate solar system model and a Sun-Earth-NEO three-body system when the NEOs are close to Earth to search for NEOs with low-energy orbits. It is possible for such an NEO to be temporarily captured by Earth; its orbit would thereby be changed and it would become an Earth-orbiting object after a small...

  10. Asteroids - NeoWs API

    Data.gov (United States)

    National Aeronautics and Space Administration — NeoWs (Near Earth Object Web Service) is a RESTful web service for near earth Asteroid information. With NeoWs a user can: search for Asteroids based on their...

  11. 从日地系统L2出发借力月球飞越近地小行星%Near-Earth Asteroid Flyby Trajectories from the Sun-Earth L2 via Lunar Gravity Assist

    Institute of Scientific and Technical Information of China (English)

    何胜茂; 彭超; 高扬

    2016-01-01

    There are several flight options for the Chang’E-2 spacecraft after its remaining at the Sun-Earth L2 point, for example, impacting the Moon or recapture into lunar orbit, returning to Earth orbit or atmospheric reentry, heading for halo orbits of the Earth-Moon L1 or L2 or the Sun-Earth L1 point, as well as flying by near-Earth asteroids in interplanetary space (Finally, Chang’E-2 successfully implemented a close flyby of Toutatis, a potentially hazardous near-Earth asteroid, on Dec.13, 2012). The analyses of these flight options require designing preliminary transfer trajectories with total velocity impulses no more than 100 m/s in four-body dynamics, in which the motion of the spacecraft is influenced by the gravities of the Sun, Earth, and Moon. In this study, we shall present low-energy Toutatis flyby trajectories from a Sun-Earth L2 quasi-periodic orbit, specifically, via a single lunar gravity assist that is intentionally utilized for exploring potential benefits, compared with the direct transfer manner that is adopted in the practical mission. Compared with the direct transfer trajectories to the asteroid, lunar gravity assist is demonstrated to be capable of saving propellant for the Toutatis flyby mission, and the equivalent velocity impulses are 58.46 m/s.%对于停留在日地系统L2的“嫦娥2号”探测器,其后续飞行方案有多个选项,例如主动撞月或重返月球轨道、返回地球轨道或再入大气、飞往地月系统L1/L2或日地系统L1、进入深空飞越近地小行星(最终,“嫦娥2号”于2012年12月13日成功地实现了对Toutatis小行星的近距离飞越)。探讨上述的飞行方案需要对飞行轨道进行初步设计,总的速度脉冲限制在100 m/s以内并且需要考虑探测器同时受到太阳、地球、月球的引力作用。本研究设计了探测器从日地系统L2出发借力月球实现Toutatis小行星飞越的飞行方案,与直接飞越方案相比

  12. An investigation of the low-ΔV near-Earth asteroids (341843) 2008 EV5 and (52381) 1993 HA. Two suitable targets for the ARM and MarcoPolo-M5 space missions

    Science.gov (United States)

    Perna, D.; Popescu, M.; Monteiro, F.; Lantz, C.; Lazzaro, D.; Merlin, F.

    2017-01-01

    Context. The Asteroid Redirect Mission (ARM) under development by NASA is being planned to collect a multi-meter boulder from a near-Earth asteroid (NEA), and to bring it to the cis-lunar space in the mid-2020's for future study and exploitation by a crewed mission. The MarcoPolo-M5 project is being proposed in 2016 for the M5 mission opportunity by ESA, to bring back to Earth a sample from a very primitive D-type NEA. As D-types are very rare within the NEA population, considerable effort is still in progress to characterize easily accessible targets with unknown surface composition, in order to discover further asteroids that belong to this taxonomic group. Aims: We aim to further characterize the physical properties of two optimal targets for sample return space missions, the low-ΔV NEAs (341843) 2008 EV5 and (52381) 1993 HA. The asteroid 2008 EV5 is the baseline target of ARM, but only one spectrum of this object exists in the literature. The asteroid 1993 HA is a very favourable target for a space mission based on its dynamical properties: here we intend to assess if it is a suitable target for MarcoPolo-M5. Methods: We obtained visible spectroscopy of 2008 EV5 with the FORS2 instrument at ESO-VLT (Paranal, Chile), at different rotational phases. We also obtained visible and near-infrared spectroscopy of 1993 HA, using the EFOSC2 and SOfI instruments at ESO-NTT (La Silla, Chile). Visible photometry of 1993 HA was carried out within the IMPACTON project at the Observatório Astronômico do Sertão de Itaparica (Itacuruba, Brazil). Results: Our new observations are in agreement with the C-type classification of 2008 EV5, which is a requirement for the ARM mission. We obtained five visible spectra which do not show any variability within the limits of noise, suggesting a homogeneous surface. We obtained the first ever spectroscopic dataset ( 0.4-1.6 μm) for 1993 HA, finding a featureless, red-sloped behaviour typical of D-types (a T or X classification is also

  13. Mid-infrared Spectra of Binary Asteroids With Spitzer/IRS

    NARCIS (Netherlands)

    Marchis, Franck; Emery, J. P.; Iglesias, J.; Pollock, J.; Mueller, M.; Harris, A. W.; Michalowski, T.; Berthier, J.; Descamps, P.

    2008-01-01

    To date, 162 asteroids are known to be binary or multiple systems. Insights, such as the size and shape of their components, the nature of their surface, their bulk density are the key to understanding how these multiple asteroidal systems formed. We obtained 19.9h of observations using the Spitzer/

  14. Mid-infrared Spectra of Binary Asteroids With Spitzer/IRS

    NARCIS (Netherlands)

    Marchis, Franck; Emery, J. P.; Iglesias, J.; Pollock, J.; Mueller, M.; Harris, A. W.; Michalowski, T.; Berthier, J.; Descamps, P.

    2008-01-01

    To date, 162 asteroids are known to be binary or multiple systems. Insights, such as the size and shape of their components, the nature of their surface, their bulk density are the key to understanding how these multiple asteroidal systems formed. We obtained 19.9h of observations using the Spitzer/

  15. Mid-infrared Spectra of Binary Asteroids With Spitzer/IRS

    NARCIS (Netherlands)

    Marchis, Franck; Emery, J. P.; Iglesias, J.; Pollock, J.; Mueller, M.; Harris, A. W.; Michalowski, T.; Berthier, J.; Descamps, P.

    2008-01-01

    To date, 162 asteroids are known to be binary or multiple systems. Insights, such as the size and shape of their components, the nature of their surface, their bulk density are the key to understanding how these multiple asteroidal systems formed. We obtained 19.9h of observations using the

  16. Near-Earth objects finding them before they find us

    CERN Document Server

    Yeomans, Donald K

    2012-01-01

    Of all the natural disasters that could befall us, only an Earth impact by a large comet or asteroid has the potential to end civilization in a single blow. Yet these near-Earth objects also offer tantalizing clues to our solar system's origins, and someday could even serve as stepping-stones for space exploration. In this book, Donald Yeomans introduces readers to the science of near-Earth objects--its history, applications, and ongoing quest to find near-Earth objects before they find us. In its course around the sun, the Earth passes through a veritable shooting gallery of million

  17. Ejecta cloud from the AIDA space project kinetic impact on the secondary of a binary asteroid: I. mechanical environment and dynamical model

    Science.gov (United States)

    Yu, Yang; Michel, Patrick; Schwartz, Stephen R.; Naidu, Shantanu P.; Benner, Lance A. M.

    2017-01-01

    An understanding of the post-impact dynamics of ejecta clouds are crucial to the planning of a kinetic impact mission to an asteroid, and also has great implications for the history of planetary formation. The purpose of this article is to track the evolution of ejecta produced by AIDA mission, which targets for kinetic impact the secondary of near-Earth binary asteroid (65803) Didymos on 2022, and to feedback essential informations to AIDA's ongoing phase-A study. We present a detailed dynamic model for the simulation of an ejecta cloud from a binary asteroid that synthesizes all relevant forces based on a previous analysis of the mechanical environment. We apply our method to gain insight into the expected response of Didymos to the AIDA impact, including the subsequent evolution of debris and dust. The crater scaling relations from laboratory experiments are employed to approximate the distributions of ejecta mass and launching speed. The size distribution of fragments is modeled with a power law fitted from observations of real asteroid surface. A full-scale demonstration is simulated using parameters specified by the mission. We report the results of the simulation, which include the computed spread of the ejecta cloud and the recorded history of ejecta accretion and escape. The violent period of the ejecta evolution is found to be short, and is followed by a stage where the remaining ejecta is gradually cleared. Solar radiation pressure proves to be efficient in cleaning dust-size ejecta, and the simulation results after two weeks shows that large debris on polar orbits (perpendicular to the binary orbital plane) has a survival advantage over smaller ejecta and ejecta that keeps to low latitudes.

  18. First known terrestrial impact of a binary asteroid from a main belt breakup event.

    Science.gov (United States)

    Ormö, Jens; Sturkell, Erik; Alwmark, Carl; Melosh, Jay

    2014-10-23

    Approximately 470 million years ago one of the largest cosmic catastrophes occurred in our solar system since the accretion of the planets. A 200-km large asteroid was disrupted by a collision in the Main Asteroid Belt, which spawned fragments into Earth crossing orbits. This had tremendous consequences for the meteorite production and cratering rate during several millions of years following the event. The 7.5-km wide Lockne crater, central Sweden, is known to be a member of this family. We here provide evidence that Lockne and its nearby companion, the 0.7-km diameter, contemporaneous, Målingen crater, formed by the impact of a binary, presumably 'rubble pile' asteroid. This newly discovered crater doublet provides a unique reference for impacts by combined, and poorly consolidated projectiles, as well as for the development of binary asteroids.

  19. A possible mechanism to explain the lack of binary asteroids among the Plutinos

    Science.gov (United States)

    Compère, A.; Farrelly, D.; Lemaître, A.; Hestroffer, D.

    2013-10-01

    Context. Binary asteroids are common in the solar system, including in the Kuiper belt. However, there seems to be a marked disparity between the binary populations in the classical part of the Kuiper belt and the part of the belt in the 3:2 resonance with Neptune - i.e., the region inhabited by the Plutinos. In particular, binary Plutinos are extremely rare. Aims: We study the impact of the 3:2 resonance on the formation of Kuiper belt binaries, according to the Nice model, in order to explain such phenomenon. Methods: Numerical simulations are performed within the 2 + 2 body approximation (Sun/Neptune + binary partners). The MEGNO chaos indicator is used to map out regular and chaotic regions of phase space. Residence times of test (binary) particles within the Hill sphere are compared inside and outside of the 3:2 resonance. The effect of increasing the heliocentric eccentricity of the centre of mass of the binary system is studied. This is done because mean-motion resonances between a planet and an asteroid usually have the effect of increasing the eccentricity of the asteroid. Results: The stable zones in the MEGNO maps are mainly disrupted in the resonant, eccentric case: the number of binary asteroids created in this case is significantly lower than outside the 3:2 resonance. Conclusions: In the 2 + 2 body approximation, the pumping of the eccentricity of the centre of mass of a potential binary destabilises the formation of binaries. This may be a factor in explaining the scarcity of binaries in the Plutino population.

  20. THE PUZZLING MUTUAL ORBIT OF THE BINARY TROJAN ASTEROID (624) HEKTOR

    Energy Technology Data Exchange (ETDEWEB)

    Marchis, F.; Cuk, M. [Carl Sagan Center at the SETI Institute, Mountain View, CA 94043 (United States); Durech, J. [Astronomical Institute, Faculty of Mathematics and Physics, Charles University, Prague (Czech Republic); Castillo-Rogez, J. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Vachier, F.; Berthier, J. [IMCCE-Obs de Paris, F-75014 Paris (France); Wong, M. H.; Kalas, P.; Duchene, G. [Department of Astronomy, University of California at Berkeley, Berkeley, CA 94720 (United States); Van Dam, M. A. [Flat Wavefronts, Christchurch 8140 (New Zealand); Hamanowa, H. [Hamanowa Observatory, Motomiya, Fukushima 969-1204 (Japan); Viikinkoski, M., E-mail: fmarchis@seti.org [Tampere University of Technology, FI-33101 Tampere (Finland)

    2014-03-10

    Asteroids with satellites are natural laboratories to constrain the formation and evolution of our solar system. The binary Trojan asteroid (624) Hektor is the only known Trojan asteroid to possess a small satellite. Based on W. M. Keck adaptive optics observations, we found a unique and stable orbital solution, which is uncommon in comparison to the orbits of other large multiple asteroid systems studied so far. From lightcurve observations recorded since 1957, we showed that because the large Req = 125 km primary may be made of two joint lobes, the moon could be ejecta of the low-velocity encounter, which formed the system. The inferred density of Hektor's system is comparable to the L5 Trojan doublet (617) Patroclus but due to their difference in physical properties and in reflectance spectra, both captured Trojan asteroids could have a different composition and origin.

  1. The disposition of impact ejecta resulting from the AIDA-DART mission to binary asteroid 65803 Didymos: an independent investigation

    Science.gov (United States)

    Richardson, James E.; O'Brien, David P.

    2016-10-01

    If all goes as planned, in the year 2020 a joint ESA and NASA mission will be launched that will rendezvous with the near-Earth binary asteroid system 65803 Didymos in the fall of 2022. The European component, the Asteroid Impact & Deflection Assessment (AIDA) spacecraft will arrive first and characterize the system, which consists of a ~800 m diameter primary and a ~160 m diameter secondary, orbiting a common center of mass at a semi-major axis distance of ~1200 m with a orbital period of 11.9 hr. Following system characterization, the AIDA spacecraft will remove to a safe distance while the NASA component, the 300 kg Double Asteroid Redirection Test (DART) spacecraft collides with the trailing edge of the secondary body (with respect to the binary's retrograde mutual orbit). Meanwhile, the AIDA spacecraft will conduct observations of this impact and its aftermath, specifically looking for changes made to the primary, the secondary, and their mutual orbit as a result of the DART collision. Of particular interest is the ballistic flight and final disposition of the ejecta produced by the impact cratering process, not just from the standpoint of scientific study, but also from the standpoint of AIDA spacecraft safety.In this study, we investigate a series of hypothetical DART impacts utilizing a semi-empirical, numerical impact ejecta plume model originally developed for the Deep Impact mission and designed specifically with impacts on small bodies in mind. The resulting excavated mass is discretized into 7200 individual tracer particles, each representing a unique combination of speed, mass, and ejected direction. The trajectory of each tracer is computed numerically under the gravitational influence of both primary and secondary, along with the effects of solar radiation pressure. Each tracer is followed until it either impacts a body or escapes the system, whereupon tracking is continued in the heliocentric frame using an N-body integrator. Various impact

  2. Near Earth Object Survey Telescope

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The Near Earth Object Survey Telescope (NEOST), located at the Xuyi station of the Purple Mountain Observatory, is a telescope with the most powerful detection capacity, the highest efficiency and the best performance in the fields of near Earth object survey and optical imaging in China. NEOST is an 171.8 Schmidt type telescope with a 1.20 meter primary mirror and a 1.04 meter corrector,

  3. Observations of Candidate Binary Asteroids in the Jovian Trojan and Hilda Populations

    Science.gov (United States)

    Sonnett, Sarah M.; Mainzer, Amy K.; Grav, Tommy; Masiero, Joseph R.; Bauer, James M.; Kramer, Emily A.

    2016-10-01

    Jovian Trojans (hereafter, Trojans) are asteroids in stable orbits at Jupiter's L4 and L5 Lagrange points, and Hilda asteroids are inwards of the Trojans in 3:2 mean-motion resonance with Jupiter. Due to their special dynamical properties, observationally constraining the formation location and dynamical histories of Trojans and HIldas offers key input for giant planet migration models. A fundamental parameter in assessing formation location is the bulk density - with low-density objects associated with an ice-rich formation environment in the outer solar system and high-density objects typically linked to the warmer inner solar system. Bulk density can only be directly measured during a close fly-by or by determining the mutual orbits of binary asteroid systems. With the aim of determining densities for a statistically significant sample of Trojans and Hildas, we are undertaking an observational campaign to confirm and characterize candidate binary asteroids published in Sonnett et al. (2015). These objects were flagged as binary candidates because their large NEOWISE brightness variations imply shapes so elongated that they are not likely explained by a singular equilibrium rubble pile and instead may be two elongated, gravitationally bound asteroids. We are obtaining densely sampled rotational light curves of these possible binaries to search for light curve features diagnostic of binarity and to determine the orbital properties of any confirmed binary systems by modeling the light curve. We present preliminary results from the follow-up campaign of these candidates, including estimates on the densities of objects that appear to be in binary systems and the binary fraction for Trojans and Hildas.

  4. Asteroid Impact and Deflection Assessment mission: the Double Asteroid Redirection Test (DART)

    Science.gov (United States)

    Cheng, A.; Michel, P.

    2015-10-01

    The Asteroid Impact & Deflection Assessment (AIDA) mission will be the first space experiment to demonstrate asteroid impact hazard mitigation by using a kinetic impactor. AIDA is a joint ESA-NASA cooperative project, which includes the ESA Asteroid Impact Mission (AIM) rendezvous spacecraft and the NASA Double Asteroid Redirection Test (DART) mission. The AIDA target is the near-Earth binary asteroid 65803 Didymos, which will make an unusually close approach to Earth in October, 2022. The ~300-kg DART spacecraft is designed to impact the Didymos secondary at 6.5 km/s and demonstrate the ability to modify its trajectory through momentum transfer. The primary goals of AIDA are (i) to investigate the binary near-Earth asteroid (65803) Didymos, (ii) to demonstrate asteroid deflection by kinetic impact and to characterize the deflection. The primary DART objectives are to demonstrate a hypervelocity impact on the Didymos moon and to determine the resulting deflection from ground-based observatories. The DART impact on the Didymos secondary will cause a measurable change in the orbital period of the binary.

  5. Period Determination of Binary Asteroid Targets Observed at Hunters Hill Observatory: May-September 2009

    Science.gov (United States)

    Higgins, David; Oey, Julian; Pravec, Petr

    2011-01-01

    Lightcurves for seven confirmed or possible binary asteroids were obtained at the Hunters Hill Observatory (HHO) and Leura Observatory from 2009 May through 2010 September: 1453 Fennia, 2501 Lohja, 3076 Garbor, 4029 Bridges, 5325 Silver, 6244 Okamoto, and (6265) 1985 TW3.

  6. Asteroid mining

    Science.gov (United States)

    Gertsch, Richard E.

    1992-01-01

    The earliest studies of asteroid mining proposed retrieving a main belt asteroid. Because of the very long travel times to the main asteroid belt, attention has shifted to the asteroids whose orbits bring them fairly close to the Earth. In these schemes, the asteroids would be bagged and then processed during the return trip, with the asteroid itself providing the reaction mass to propel the mission homeward. A mission to one of these near-Earth asteroids would be shorter, involve less weight, and require a somewhat lower change in velocity. Since these asteroids apparently contain a wide range of potentially useful materials, our study group considered only them. The topics covered include asteroid materials and properties, asteroid mission selection, manned versus automated missions, mining in zero gravity, and a conceptual mining method.

  7. Dynamics of Rotationally Fissioned Asteroids

    Science.gov (United States)

    Jacobson, Seth A.; Scheeres, D. J.

    2010-10-01

    We present a model for near-Earth asteroid (NEA) rotational fission that results in the evolution of all observed types of NEA systems: synchronous binaries, asteroid pairs, doubly synchronous binaries, high-e binaries, ternary systems, and contact binaries. The model consists of "rubble pile” asteroid geophysics, the YORP and binary YORP effects, and mutual gravitational interactions. An NEA can be modeled as a ``rubble pile"--a collection of gravitationally bound boulders with a distribution of size scales and very little tensile strength between them. The YORP effect torques a "rubble pile” asteroid until the asteroid reaches its disruption spin limit, and then two collections of boulders will enter into orbit about each other determined by the largest distance between mass centers. This binary system dynamically evolves under the effects of non-spherical gravitational potentials, solar gravitational perturbations, and mutual body tides. The coupling between the spin states and orbit state chaotically drives the system into the observed asteroid classes with mass ratio, q, distinguishing two evolutionary tracks. High mass ratio systems, q>0.2, evolve tidally into doubly synchronous binaries and then continued to be evolved by BYORP. Low mass ratio systems, qfission, creating a chaotic ternary system. We call this new process secondary fission. The resulting triple system may eject one body or, more often, send one into a slow speed impact with the primary. These processes tend to stabilize the initially chaotic binaries to create synchronous binaries. These results emphasize the importance of the initial component size distribution and configuration within the parent body. This work is supported by NASA's PGG and OPR programs through grants: NNX08AL51G and NNX09AU23G.

  8. A Newborn Asteroid Family of Likely Rotational Origin Harboring a Doubly-Synchronous Binary

    Science.gov (United States)

    Drahus, Michal; Waniak, Waclaw

    2016-10-01

    From the total number of about twenty active asteroids identified to date, one of the most intriguing is P/2012 F5. The 2-km sized object has a short rotation period of 3.24 hr – the shortest known among main-belt active asteroids and comets – and is trailed by several fragments recently separated from the main nucleus (Drahus et al. 2015, ApJL 802, L8). Our extensive observations with Hubble in late 2015 and early 2016 have revealed that the fragments are real and stable "baby asteroids", still cocooned in their birth dust trail. Consequently, P/2012 F5 is the first known asteroid family forming in the present-day epoch. Given the rapid spin of the main nucleus, the system is also the best candidate for the first "rotational" asteroid family originating from rotational fission (as opposed to the long-known "collisional" families), extending the recently identified class of asteroid pairs (Pravec et al. 2010, Nature 466, 1085). Furthermore, the HST data allowed us to measure a light curve of the brightest fragment of P/2012 F5, several magnitudes fainter than the main nucleus. The light curve has all the characteristics of a close binary with significantly elongated, roughly equal sized components, having equal rotation and orbital periods of about 9 hr. The existence of a doubly-synchronous binary in an ultra-young asteroid family is seemingly inconsistent with the established "slow" binary formation path, in which YORP torques first lead to rotational fission and then tides lead to synchronization (Jacobson & Scheeres 2011, Icarus 214, 161). Instead, we believe that the object fissioned while orbiting the main nucleus and drawing its angular momentum, and was subsequently ejected from the system as a finished doubly-synchronous binary. This scenario is consistent with computer simulations in that the timescales for secondary fission and ejection from the system are indeed very short (Jacobson & Scheeres 2011, Icarus 214, 161). But the empirical evidence that

  9. Asteroid structure

    Science.gov (United States)

    Asphaug, E.

    2014-07-01

    Even before the first space missions to asteroids, in the mid-1990s, it was known that asteroids have weird structures. Photometry indicated complicated shapes, and the pioneering radar investigations by Ostro and colleagues followed by adaptive optics campaigns and flybys showed odd binary forms, and confirmed the common presence of satellites, and indications of highly varying surface roughness. Some asteroids turned out to be dominated by a single major cratering event, while others showed no evidence of a major crater, or perhaps for global crater erasure. The first space mission to orbit an asteroid, NEAR, found a mixture of heavily cratered terrains and geomorphically active 'ponds', and indicated evidence for global seismicity from impact. The next mission to orbit an asteroid, Hayabusa, found what most agree is a rubble pile, with no major craters and an absence of fines. There is to date no direct evidence of asteroid interior geology, other than measurements of bulk density, and inferences made for mass distribution asymmetry based on dynamics, and inferences based on surface lineaments. Interpolating from the surface to the interior is always risky and usually wrong, but of course the answer is important since we are someday destined to require this knowledge in order to divert a hazardous asteroid from impact with the Earth. Even considering the near-subsurface, here we remain as ignorant as we were about the Moon in the early 1960s, whether the surface will swallow us up in dust, or will provide secure landing and anchoring points. Laboratory experimentation in close to zero-G is still in its early stages. Adventures such as mining and colonization will surely have to wait until we better know these things. How do we get from here to there? I will focus on 3 areas of progress: (1) asteroid cratering seismology, where we use the surface craters to understand what is going on inside; (2) numerical modeling of collisions, which predicts the internal

  10. Tidal Evolution of Asteroidal Binaries. Ruled by Viscosity. Ignorant of Rigidity

    CERN Document Server

    Efroimsky, Michael

    2015-01-01

    The rate of tidal evolution of asteroidal binaries is defined by the dynamical Love numbers divided by quality factors. Common is the (often illegitimate) approximation of the dynamical Love numbers with their static counterparts. As the static Love numbers are, approximately, proportional to the inverse rigidity, this renders a popular fallacy that the tidal evolution rate is determined by the product of the rigidity by the quality factor: $\\,k_l/Q\\propto 1/(\\mu Q)\\,$. In reality, the dynamical Love numbers depend on the tidal frequency and all rheological parameters of the tidally perturbed body (not just rigidity). We demonstrate that in asteroidal binaries the rigidity of their components plays virtually no role in tidal friction and tidal lagging, and thereby has almost no influence on the intensity of tidal interactions (tidal torques, tidal dissipation, tidally induced changes of the orbit). A key quantity that determines the tidal evolution is a product of the effective viscosity $\\,\\eta\\,$ by the tid...

  11. Shapes of binary asteroid primaries from photometric observations

    Science.gov (United States)

    Scheirich, Peter

    2016-10-01

    I will present results from a method which combine lightcurve inversion for single bodies and the method for inversion of lightcurves of occulting/eclipsing binary systems. A code developed by M. Kaasalainen and J. Durech for inversion of lightcurves of single bodies is adapted to fit our purposes. The original code uses a slightly elongated ellipsoid as an initial shape for optimization. We substituted this ellipsoid with a variety of shapes using Gaussian random spheres. This allowed the optimization algorithm to iterate to a range of final shapes.For each binary system, the short-period (rotational) component of its lightcurve is inverted using this code and a set of possible shapes of the primary are obtained. In the next step these shape models of the primary are, one by one, incorporated into the full model of the binary system and complete photometric data including the mutual events are fitted. Comparing synthetic lightcurves of the best-fit solutions with the observed data enables another narrowing of the selection of the possible shapes of the primary. This process is based on the times of phases of mutual events occurring on different geometries (i.e. the secondary passing in front of/behind the primary not only equator-on).We will also test a hypothesis that most of the primaries of the binary systems are similar in shape to each other. A figure resembling the shape of the primary of 1999 KW4, i.e., the top-shaped object with an equatorial ridge, will be used for the primary's shape. Its main characteristics – a polar flattening and width and height of the equatorial ridge, will be used as independent parameters. A variety of the shapes generated by a combination of these parameters will be used as an initial shapes for the optimization using the code described above.The work is supported by the Grant Agency of the Czech Republic, Grant 15-07193S.

  12. Double Asteroid Redirection Test (DART)

    Science.gov (United States)

    Cheng, A. F.

    2016-12-01

    The Asteroid Impact Deflection Assessment (AIDA) mission will be the first space experiment to demonstrate asteroid impact hazard mitigation by using a kinetic impactor. AIDA is a joint ESA-NASA cooperative project, consisting of the NASA Double Asteroid Redirection Test (DART) kinetic impactor mission and the ESA Asteroid Impact Mission (AIM) which is the rendezvous spacecraft. The AIDA target is the near-Earth binary asteroid 65803 Didymos. During the Didymos close approach to Earth in October, 2022, the DART spacecraft will impact the Didymos secondary at 6 km/s and deflect its trajectory, changing the orbital period of the binary. This change can be measured by Earth-based optical and radar observations. The primary goals of AIDA are to (1) perform a full-scale demonstration of asteroid deflection by kinetic impact; (2) measure the resulting deflection; and (3) validate and improve models for momentum transfer in high-speed impacts on an asteroid. The combined DART and AIM missions will provide the first measurements of momentum transfer efficiency from a kinetic impact at full scale on an asteroid, where the impact conditions of the projectile are known, and physical properties and internal structures of the target asteroid are also characterized. In addition to a measurable change in the binary orbit period, the DART kinetic impact is predicted to induce forced librations of the Didymos secondary of up to several degrees amplitude. It will furthermore make a crater that will be studied in detail by the AIM spacecraft, and it will release a volume of particulate ejecta that may be directly observable from Earth or even resolvable as a coma or an ejecta tail by ground-based telescopes. Updates will be given on DART status and study results.

  13. Chang'e-2 spacecraft observations of asteroid 4179 Toutatis

    Science.gov (United States)

    Ji, Jianghui; Jiang, Yun; Zhao, Yuhui; Wang, Su; Yu, Liangliang

    2016-01-01

    On 13 December 2012, Chang'e-2 completed a successful flyby of the near-Earth asteroid 4179 Toutatis at a closest distance of 770 meters from the asteroid's surface. The observations show that Toutatis has an irregular surface and its shape resembles a ginger-root of a smaller lobe (head) and a larger lobe (body). Such bilobate shape is indicative of a contact binary origin for Toutatis. In addition, the high-resolution images better than 3 meters provide a number of new discoveries about this asteroid, such as an 800-meter depression at the end of the large lobe, a sharply perpendicular silhouette near the neck region, boulders, indicating that Toutatis is probably a rubble-pile asteroid. Chang'e-2 observations have significantly revealed new insights into the geological features and the formation and evolution of this asteroid. In final, we brief the future Chinese asteroid mission concept.

  14. Chang'e-2 spacecraft observations of asteroid 4179 Toutatis

    CERN Document Server

    Ji, Jianghui; Zhao, Yuhui; Wang, Su; Yu, Liangliang

    2015-01-01

    On 13 December 2012, Chang'e-2 completed a successful flyby of the near-Earth asteroid 4179 Toutatis at a closest distance of 770 meters from the asteroid's surface. The observations show that Toutatis has an irregular surface and its shape resembles a ginger-root of a smaller lobe (head) and a larger lobe (body). Such bilobate shape is indicative of a contact binary origin for Toutatis. In addition, the high-resolution images better than 3 meters provide a number of new discoveries about this asteroid, such as an 800-meter depression at the end of the large lobe, a sharply perpendicular silhouette near the neck region, boulders, indicating that Toutatis is probably a rubble-pile asteroid. Chang'e-2 observations have significantly revealed new insights into the geological features and the formation and evolution of this asteroid. In final, we brief the future Chinese asteroid mission concept.

  15. Comparing near-surface and bulk densities of asteroids using radar scattering properties

    Science.gov (United States)

    Zambrano Marin, Luisa Fernanda; Nolan, Michael C.; Taylor, Patrick A.; Virkki, Anne

    2016-10-01

    Dual-polarization radar measurements of asteroids provide a joint constraint on the near-surface density and porosity, which can give insights on asteroid composition and evolution. Magri et al. (2001) used (433) Eros radar and spacecraft data as calibration for estimating the near-surface densities and porosities of 45 other radar-detected asteroids (36 main-belt and 9 near-Earth). At that time, only (433) Eros had both radar observations and a measured bulk density. Now that there have been spacecraft observations of several other asteroids and radar measurements of the densities of several binary near-Earth asteroids with various compositions, we can expand the calibration to include those objects. We begin by applying the method of Magri et al. to Ceres, Vesta, Itokawa, 1994 CC, 2001 SN263, 1998 QE2, and 2000 DP107 to explore the differences between the bulk density and the near-surface density measured with radar. We expect significant differences between Ceres and Vesta and the small near-Earth asteroids as the porosities of these objects are expected to be quite different. However, we expect that small binary objects likely have similar internal structures, so that any differences should depend on composition and perhaps surface weathering.Reference: Magri et al., "Radar constraints on asteroid Properties using 433 Eros as ground truth". Meteoritics & Planetary Science 36, 1697-1709, 2001.

  16. Near-Earth object intercept trajectory design for planetary defense

    Science.gov (United States)

    Vardaxis, George; Wie, Bong

    2014-08-01

    Tracking the orbit of asteroids and planning for asteroid missions have ceased to be a simple exercise, and become more of a necessity, as the number of identified potentially hazardous near-Earth asteroids increases. Several software tools such as Mystic, MALTO, Copernicus, SNAP, OTIS, and GMAT have been developed by NASA for spacecraft trajectory optimization and mission design. However, this paper further expands upon the development and validation of an Asteroid Mission Design Software Tool (AMiDST), through the use of approach and post-encounter orbital variations and analytic keyhole theory. Combining these new capabilities with that of a high-precision orbit propagator, this paper describes fictional mission trajectory design examples of using AMiDST as applied to a fictitious asteroid 2013 PDC-E. During the 2013 IAA Planetary Defense Conference, the asteroid 2013 PDC-E was used for an exercise where participants simulated the decision-making process for developing deflection and civil defense responses to a hypothetical asteroid threat.

  17. Dumb-bell-shaped equilibrium figures for fiducial contact-binary asteroids and EKBOs

    Science.gov (United States)

    Descamps, Pascal

    2015-01-01

    In this work, we investigate the equilibrium figures of a dumb-bell-shaped sequence with which we are still not well acquainted. Studies have shown that these elongated and nonconvex figures may realistically replace the classic “Roche binary approximation” for modeling putative peanut-shaped or contact binary asteroids. The best-fit dumb-bell shapes, combined with the known rotational period of the objects, provide estimates of the bulk density of these objects. This new class of mathematical figures has been successfully tested on the observed light curves of three noteworthy small bodies: main-belt Asteroid 216 Kleopatra, Trojan Asteroid 624 Hektor and Edgeworth-Kuiper-belt object 2001 QG298. Using the direct observations of Kleopatra and Hektor obtained with high spatial resolution techniques and fitting the size of the dumb-bell-shaped solutions, we derived new physical characteristics in terms of equivalent radius, 62.5 ± 5 km and 92 ± 5 km, respectively, and bulk density, 4.4 ± 0.4 g cm-3 and 2.43 ± 0.35 g cm-3, respectively. In particular, the growing inadequacy of the radar shape model for interpreting any type of observations of Kleopatra (light curves, AO images, stellar occultations) in a satisfactory manner suggests that Kleopatra is more likely to be a dumb-bell-shaped object than a “dog-bone.”

  18. Dumb-bell-shaped equilibrium figures for fiducial contact-binary asteroids and EKBOs

    CERN Document Server

    Descamps, Pascal

    2014-01-01

    In this work, we investigate the equilibrium figures of a dumb-bell-shaped sequence with which we are still not well acquainted. Studies have shown that these elongated and nonconvex figures may realistically replace the classic "Roche binary approximation" for modeling putative peanut-shaped or contact binary asteroids. The best-fit dumb-bell shapes, combined with the known rotational period of the objects, provide estimates of the bulk density of these objects. This new class of mathematical figures has been successfully tested on the observed light curves of three noteworthy small bodies: main-belt asteroid 216 Kleopatra, Trojan asteroid 624 Hektor and Edgeworth-Kuiper-belt object 2001 QG298. Using the direct observations of Kleopatra and Hektor obtained with high spatial resolution techniques and fitting the size of the dumb-bell-shaped solutions, we derived new physical characteristics in terms of equivalent radius and bulk density. In particular, the growing inadequacy of the radar shape model for inter...

  19. Exploring the Near Earth Object Population

    Science.gov (United States)

    Bottke, W.

    2013-09-01

    This is a golden age for NEA research. We have discovered some 95% of the most threatening NEAs (those larger than 1 km, Mainzer et al. 2012), while ongoing surveys (e.g., Catalina Sky Survey) are finding many sub-km NEAs as well. NEA physical characterization studies by missions (e.g., NEARShoemaker), space-based telescopes (e.g., WISE), and ground-based observatories (e.g., Arecibo, IRTF), are also revolutionizing our ideas about what NEAs are actually like. The OSIRIS-REx mission will return a sample from Bennu, a carbonaceous chondrite-like NEO in 2020, while President Obama announced on April 15, 2010 that NASA would send astronauts to an NEA by 2025. The Feb. 15 explosion of an NEA over Chelyabinsk, Russia, has further boosted interest in NEAs. In my talk, I will discuss several recent advances in our understanding of the NEO population (e.g, how they go from their source regions to their observed orbits; what we know about the size and nature of the population). I will give particular attention to candidates for robotic and human missions, namely those NEOs on near-Earth like orbits. Recent work has shown that a population of asteroids exists that have been temporarily captured in orbit around Earth ("minimoons"). They offer an innovative, but heretofore uninvestigated, population of targets for human exploration because of their proximity to the Earth and their low geocentric velocities. By better understanding them, we can test theories of the creation, internal structure, and transport of small asteroids. The largest minimoons in the steady state population are 1 to 2 meters in diameter, sizable enough to be both scientifically interesting and potentially suitable as destinations.

  20. The global impact distribution of Near-Earth objects

    CERN Document Server

    Rumpf, Clemens; Atkinson, Peter M

    2015-01-01

    Asteroids that could collide with the Earth are listed on the publicly available Near-Earth object (NEO) hazard web sites maintained by the US and European space agencies (NASA and ESA). The impact probability distribution of 69 potentially threatening NEOs from these lists that produce 261 dynamically distinct impact instances, or Virtual Impactors (VIs), were calculated using the Asteroid Risk Mitigation and Optimization Research (ARMOR) tool in conjunction with OrbFit. ARMOR projected the impact probability of each VI onto the surface of the Earth as a spatial probability distribution. The projection considers orbit solution accuracy and the global impact probability. The method of ARMOR is introduced and the tool is validated against two asteroid-Earth collision cases with objects 2008 TC3 and 2014 AA. In the analysis, the natural distribution of impact corridors is contrasted against the impact probability distribution to evaluate the distributions conformity with the uniform impact distribution assumpti...

  1. Observations of Near Earth Objects with Spitzer

    Science.gov (United States)

    Trilling, David E.; Mommert, Michael; Hora, Joseph L.; Chesley, Steven R.; Emery, Joshua P.; Fazio, Giovanni G.; Harris, Alan; Mueller, Michael; Smith, Howard Alan

    2016-10-01

    We are carrying out an Exploration Science Warm Spitzer program entitled NEOSurvey in which we are observing 550 Near Earth Objects in 710 hours of Spitzer time. For each object we use a thermal model to derive diameter and albedo. For each object we also derive a (partial) lightcurve; total elapsed observing times range from 15 minutes to 3.2 hours. This catalog of 500+ NEO lightcurves is a substantial increase over the number of NEO lightcurves presently known. In addition to creating a large catalog of NEO properties, we are also able to study the properties of individual NEOs, including those with low delta V values (i.e., accessible asteroids) and those that might be dead comets. The final observations in this program will be obtained by 30 Sept 2016, so at the DPS meeting we will present a first look at our entire catalog of results. All results are posted at nearearthobjects.nau.edu usually within days of the data being released by the Spitzer Science Center. This work was supported in part by funding from the Spitzer Science Center.

  2. Artificial equilibrium points in binary asteroid systems with continuous low-thrust

    Science.gov (United States)

    Bu, Shichao; Li, Shuang; Yang, Hongwei

    2017-08-01

    The positions and dynamical characteristics of artificial equilibrium points (AEPs) in the vicinity of a binary asteroid with continuous low-thrust are studied. The restricted ellipsoid-ellipsoid model of binary system is employed for the binary asteroid system. The positions of AEPs are obtained by this model. It is found that the set of the point L1 or L2 forms a shape of an ellipsoid while the set of the point L3 forms a shape like a "banana". The effect of the continuous low-thrust on the feasible region of motion is analyzed by zero velocity curves. Because of using the low-thrust, the unreachable region can become reachable. The linearized equations of motion are derived for stability's analysis. Based on the characteristic equation of the linearized equations, the stability conditions are derived. The stable regions of AEPs are investigated by a parametric analysis. The effect of the mass ratio and ellipsoid parameters on stable region is also discussed. The results show that the influence of the mass ratio on the stable regions is more significant than the parameters of ellipsoid.

  3. Stable Orbits in the Didymos Binary Asteroid System - Useful Platforms for Exploration

    Science.gov (United States)

    Damme, Friedrich; Hussmann, Hauke; Wickhusen, Kai; Enrico, Mai; Oberst, Jürgen

    2016-04-01

    We have analyzed particle motion in binary asteroid systems to search for stable orbits. In particular, we studied the motion of particles near the asteroid 1996 GT (Didymos), proposed as a target for the AIDA mission. The combined gravity fields of the odd-shaped rotating objects moving about each other are complex. In addition, orbiting spacecraft or dust particles are affected by radiation pressure, possibly exceeding the faint gravitational forces. For the numerical integrations, we adopt parameters for size, shape, and rotation from telescopic observations. To simulate the effect of radiation pressure during a spacecraft mission, we apply a spacecraft wing-box shape model. Integrations were carried out beginning in near-circular orbits over 11 days, during which the motion of the particles were examined. Most orbits are unstable with particles escaping quickly or colliding with the asteroid bodies. However, with carefully chosen initial positions, we found stable motion (in the orbiting plane of the secondary) associated with the Lagrangian points (L4 and L5), in addition to horseshoe orbits, where particles move from one of the Lagrangian point to the other. Finally, we examined orbits in 1:2 resonances with the motion of the orbital period of the secondary. Stable conditions depend strongly on season caused by the inclination of the mutual orbit plane with respect to Didymos solar orbit. At larger distance from the asteroid pair, we find the well-known terminator orbits where gravitational attraction is balanced against radiation pressure. Stable orbits and long motion arcs are useful for long tracking runs by radio or Laser instruments and are well-suited for modelling of the ephemerides of the asteroid pair and gravity field mapping. Furthermore, these orbits may be useful as observing posts or as platforms for approach. These orbits may also represent traps for dust particles, an opportunity for dust collection - or possibly a hazard to spacecraft

  4. Tidal Evolution of Asteroidal Binaries. Ruled by Viscosity. Ignorant of Rigidity.

    Science.gov (United States)

    Efroimsky, Michael

    2015-10-01

    This is a pilot paper serving as a launching pad for study of orbital and spin evolution of binary asteroids. The rate of tidal evolution of asteroidal binaries is defined by the dynamical Love numbers kl divided by quality factors Q. Common in the literature is the (oftentimes illegitimate) approximation of the dynamical Love numbers with their static counterparts. Since the static Love numbers are, approximately, proportional to the inverse rigidity, this renders a popular fallacy that the tidal evolution rate is determined by the product of the rigidity by the quality factor: {k}l/Q\\propto 1/(μ Q). In reality, the dynamical Love numbers depend on the tidal frequency and all rheological parameters of the tidally perturbed body (not just rigidity). We demonstrate that in asteroidal binaries the rigidity of their components plays virtually no role in tidal friction and tidal lagging, and thereby has almost no influence on the intensity of tidal interactions (tidal torques, tidal dissipation, tidally induced changes of the orbit). A key quantity that overwhelmingly determines the tidal evolution is a product of the effective viscosity η by the tidal frequency χ . The functional form of the torque’s dependence on this product depends on who wins in the competition between viscosity and self-gravitation. Hence a quantitative criterion, to distinguish between two regimes. For higher values of η χ , we get {k}l/Q\\propto 1/(η χ ), {while} for lower values we obtain {k}l/Q\\propto η χ . Our study rests on an assumption that asteroids can be treated as Maxwell bodies. Applicable to rigid rocks at low frequencies, this approximation is used here also for rubble piles, due to the lack of a better model. In the future, as we learn more about mechanics of granular mixtures in a weak gravity field, we may have to amend the tidal theory with other rheological parameters, ones that do not show up in the description of viscoelastic bodies. This line of study provides

  5. ASTEROIDS

    Directory of Open Access Journals (Sweden)

    Željko Andreić

    2016-02-01

    Full Text Available Asteroids are the largest minor bodies in the Solar System. Nowadays they are in the research focus due to several facts about them: first, a subclass of asteroids can collide with Earth, and consequences of such a collision are dramatic. Second, they are now seen as source of materials that are becoming scarce on Earth, and they will be needed in future space constructions anyway. Third, they are holding clues about the origin and evolution of the Solar System. In this article, a short overview of current knowledge about asteroids is presented. Last, but not least, as several Croatian scientists were recently honored by naming an asteroid after them, a short overview of the naming process is given.

  6. The Warm Spitzer NEO Survey : Exploring The History of the Inner Solar System and Near Earth Space

    NARCIS (Netherlands)

    Hora, Joseph L.; Trilling, D. E.; Thomas, C. A.; Stansberry, J. A.; Spahr, T. B.; Smith, H. A.; Penprase, B. E.; Mueller, M.; Mainzer, A. K.; Harris, A. W.; Fazio, G. G.; Emery, J. P.; Delbo, M.; Chesley, S. R.; Bottke, W. F.; Bhattacharya, B.

    2010-01-01

    The majority of Near Earth Objects (NEOs) originated in collisions between bodies in the main asteroid belt and have found their way into near Earth space via complex and little understood dynamical interactions. This transport of material from the main belt into the inner Solar System has shaped th

  7. Asteroid flux towards circumprimary habitable zones in binary star systems: I. Statistical Overview

    CERN Document Server

    Bancelin, D; Eggl, S; Maindl, T I; Schäfer, C; Speith, R; Dvorak, R

    2015-01-01

    So far, multiple stellar systems harbor more than 130 extra solar planets. Dynamical simulations show that the outcome of planetary formation process can lead to various planetary architecture (i.e. location, size, mass and water content) when the star system is single or double. In the late phase of planetary formation, when embryo-sized objects dominate the inner region of the system, asteroids are also present and can provide additional material for objects inside the habitable zone (hereafter HZ). In this study, we make a comparison of several binary star systems and their efficiency to move icy asteroids from beyond the snow-line into orbits crossing the HZ. We modeled a belt of 10000 asteroids (remnants from the late phase of planetary formation process) beyond the snow-line. The planetesimals are placed randomly around the primary star and move under the gravitational influence of the two stars and a gas giant. As the planetesimals do not interact with each other, we divided the belt into 100 subrings ...

  8. Dynamical model of binary asteroid systems through patched three-body problems

    Science.gov (United States)

    Ferrari, Fabio; Lavagna, Michèle; Howell, Kathleen C.

    2016-08-01

    The paper presents a strategy for trajectory design in the proximity of a binary asteroid pair. A novel patched approach has been used to design trajectories in the binary system, which is modeled by means of two different three-body systems. The model introduces some degrees of freedom with respect to a classical two-body approach and it is intended to model to higher accuracy the peculiar dynamical properties of such irregular and low gravity field bodies, while keeping the advantages of having a full analytical formulation and low computational cost required. The neighborhood of the asteroid couple is split into two regions of influence where two different three-body problems describe the dynamics of the spacecraft. These regions have been identified by introducing the concept of surface of equivalence (SOE), a three-dimensional surface that serves as boundary between the regions of influence of each dynamical model. A case of study is presented, in terms of potential scenario that may benefit of such an approach in solving its mission analysis. Cost-effective solutions to land a vehicle on the surface of a low gravity body are selected by generating Poincaré maps on the SOE, seeking intersections between stable and unstable manifolds of the two patched three-body systems.

  9. ASTEROIDS

    OpenAIRE

    Željko Andreić

    2016-01-01

    Asteroids are the largest minor bodies in the Solar System. Nowadays they are in the research focus due to several facts about them: first, a subclass of asteroids can collide with Earth, and consequences of such a collision are dramatic. Second, they are now seen as source of materials that are becoming scarce on Earth, and they will be needed in future space constructions anyway. Third, they are holding clues about the origin and evolution of the Solar System. In this article, a short overv...

  10. Current problems of dynamics of moons of planets and binary asteroids based on observations

    Science.gov (United States)

    Emel'yanov, N. V.

    2017-01-01

    asteroids were determined this way. One of the principal techniques for Earth-based measurement of the masses of asteroids involves astrometric observations of binary asteroids. The determination of relative coordinates is made rather difficult by the apparent proximity of components. The success of these efforts depends on the availability of instrumentation and the expertise of observers skilled in adaptive optics and speckle interferometry. Collaboration between different research teams and observers is absolutely necessary.

  11. AIDA: Asteroid Impact & Deflection Assessment

    Science.gov (United States)

    Cheng, A. F.; Galvez, A.; Carnelli, I.; Michel, P.; Rivkin, A.; Reed, C.

    2012-12-01

    To protect the Earth from a hazardous asteroid impact, various mitigation methods have been proposed, including deflection of the asteroid by a spacecraft impact. AIDA, consisting of two mission elements, the Double Asteroid Redirection Test (DART) and the Asteroid Impact Monitoring (AIM) mission, is a demonstration of asteroid deflection. To date, there has been no such demonstration, and there is major uncertainty in the result of a spacecraft impact onto an asteroid, that is, the amount of deflection produced by a given momentum input from the impact. This uncertainty is in part due to unknown physical properties of the asteroid surface, such as porosity and strength, and in part due to poorly understood impact physics such that the momentum carried off by ejecta is highly uncertain. A first mission to demonstrate asteroid deflection would not only be a major step towards gaining the capability to mitigate an asteroid hazard, but in addition it would return unique information on an asteroid's strength, other surface properties, and internal structure. This information return would be highly relevant to future human exploration of asteroids. We report initial results of the AIDA joint mission concept study undertaken by the Johns Hopkins Applied Physics Laboratory and ESA with support from NASA centers including Goddard, Johnson and Jet Propulsion Laboratory. For AIDA, the DART spacecraft impactor study is coordinated with an ESA study of the AIM mission, which would rendezvous with the same asteroid to measure effects of the impact. Unlike the previous Don Quijote mission study performed by ESA in 2005-2007, DART envisions an impactor spacecraft to intercept the secondary member of a binary near-Earth asteroid. DART includes ground-based observations to measure the deflection independently of the rendezvous spacecraft observations from AIM, which also measures deflection and provides detailed characterization of the target asteroid. The joint mission AIDA

  12. Photometric observations of 9 Near-Earth Objects

    CERN Document Server

    Szabó, G; Sarneczky, K; Kiss, L L; Szabo, Gy.

    2001-01-01

    We present new CCD observations of nine Near-Earth Asteroids carried out between February, 1999 and July, 2000. The bulk of the data was acquired through an R_C filter, while the minor planet 11405 was observed without filter. We could determine synodic periods and amplitudes for 5 asteroids, 699: 3.3 h, 0.18 mag; 1866: 2.7 h, 0.12 mag; 1999 JD6: 7.68 h, 1.2 mag; 2000 GK137: 4.84 h, 0.27 mag; 2000 NM: 9.24 h, 0.30 mag. Based on observations taken at different phases, we could infer a phase parameter m of 0.018+/-0.005 for 1865 Cerberus. An epoch-method yielded a sidereal period of 0.27024003(5) d for this object with retrograde rotation. The remaining 3 objects have only partial coverage, thus no firm conclusion on their synodic period is possible.

  13. The Asteroid Impact Mission

    Science.gov (United States)

    Carnelli, Ian; Galvez, Andres; Mellab, Karim

    2016-04-01

    The Asteroid Impact Mission (AIM) is a small and innovative mission of opportunity, currently under study at ESA, intending to demonstrate new technologies for future deep-space missions while addressing planetary defense objectives and performing for the first time detailed investigations of a binary asteroid system. It leverages on a unique opportunity provided by asteroid 65803 Didymos, set for an Earth close-encounter in October 2022, to achieve a fast mission return in only two years after launch in October/November 2020. AIM is also ESA's contribution to an international cooperation between ESA and NASA called Asteroid Impact Deflection Assessment (AIDA), consisting of two mission elements: the NASA Double Asteroid Redirection Test (DART) mission and the AIM rendezvous spacecraft. The primary goals of AIDA are to test our ability to perform a spacecraft impact on a near-Earth asteroid and to measure and characterize the deflection caused by the impact. The two mission components of AIDA, DART and AIM, are each independently valuable but when combined they provide a greatly increased scientific return. The DART hypervelocity impact on the secondary asteroid will alter the binary orbit period, which will also be measured by means of lightcurves observations from Earth-based telescopes. AIM instead will perform before and after detailed characterization shedding light on the dependence of the momentum transfer on the asteroid's bulk density, porosity, surface and internal properties. AIM will gather data describing the fragmentation and restructuring processes as well as the ejection of material, and relate them to parameters that can only be available from ground-based observations. Collisional events are of great importance in the formation and evolution of planetary systems, own Solar System and planetary rings. The AIDA scenario will provide a unique opportunity to observe a collision event directly in space, and simultaneously from ground-based optical and

  14. Non-convex model of the binary asteroid (809) Lundia and its density estimation

    Science.gov (United States)

    Kryszczynska, A.; Bartczak, P.; Polinska, M.; Colas, F.

    2014-07-01

    Introduction: (809) Lundia was classified as a V-type asteroid in the Flora family (Florczak et.al. 2002). The binary nature of (809) Lundia was discovered in September 2005 based on photometric observations. The first modeling of the Lundia synchronous binary system was based on 22 lightcurves obtained at Borowiec and Pic du Midi Observatories during two oppositions in 2005/2006 and 2006/2007. Two methods of modeling --- modified Roche ellipsoids and kinematic --- gave similar parameters for the system (Kryszczynska et al. 2009). The poles of the orbit in ecliptic coordinates were: longitude 118° and latitude 28° in the modified Roche model and 120°, 18°, respectively, in the kinematic model. The orbital period obtained from the lightcurve analysis as well as from modeling was 15.418 h. The obtained bulk density of both components was 1.64 or 1.71 g/ccm. Observations: We observed (809) Lundia in the 2008, 2009/2010, 2011, and 2012 oppositions at the Borowiec, Pic du Midi, Prompt, and Rozhen Observatories. As predicted, the visible eclipses/occultation events were observed only in 2011. Currently, our dataset consists of 45 individual lightcurves and they were all used in the new modeling. Method: We used new method of modeling based on a genetic algorithm that is able to create a non-convex asteroid shape model, rotational period, and spin-axis orientation of a single or binary asteroid, using only photometric observations. The details of the method are presented in the poster by Bartczak et al., at this conference. Results: The new non-convex model of (809) Lundia is presented in the figure. The parameters of the system in the ecliptic coordinates are: longitude 122°, latitude 22°, and sidereal period 15.41574 h. They are very similar to the values obtained before. However, assuming an equivalent diameter of a single body of 9.1 km from the Spitzer observations (Marchis et al. 2012) and the volume of the two modeled bodies, the separation of the components

  15. ExploreNEOs: A Search for Near-Earth Objects of Cometary Origin

    NARCIS (Netherlands)

    Mommert, Michael; Harris, A. W.; Trilling, D. E.; Mueller, M.; Hora, J. L.; Delbo, M.; Bottke, W. F.; Emery, J. P.; Fazio, G.; Hagen, A. R.; Morbidelli, A.; Smith, H. A.; Thomas, C. A.

    2012-01-01

    The short dynamical lifetime of near-Earth objects (NEOs) compared to the age of the Solar System implies the existence of sources of replenishment in order to maintain the observed population of NEOs. Main belt asteroids and Jupiter family comets (JFCs), which can end up in typical NEO orbits via p

  16. ExploreNEOs: A Search for Near-Earth Objects of Cometary Origin

    NARCIS (Netherlands)

    Mommert, Michael; Harris, A. W.; Trilling, D. E.; Mueller, M.; Hora, J. L.; Delbo, M.; Bottke, W. F.; Emery, J. P.; Fazio, G.; Hagen, A. R.; Morbidelli, A.; Smith, H. A.; Thomas, C. A.

    2012-01-01

    The short dynamical lifetime of near-Earth objects (NEOs) compared to the age of the Solar System implies the existence of sources of replenishment in order to maintain the observed population of NEOs. Main belt asteroids and Jupiter family comets (JFCs), which can end up in typical NEO orbits via

  17. Near-Earth Asteorid Lightcurve Analysis at CS3-Palmer Divide Station: 2016 January-April

    Science.gov (United States)

    Warner, Brian D.

    2016-07-01

    Lightcurves for 38 near-Earth asteroids (NEAs) were obtained at the Center for Solar System Studies-Palmer Divide Station (CS3-PDS) from 2016 January-April. Also reported are 4 lightcurves obtained from 2014-2015 that were not previously published.

  18. Investigating the surface and subsurface properties of the Didymos binary asteroid with a landed CubeSat

    Science.gov (United States)

    Murdoch, Naomi; Cadu, Alexandre; Mimoun, David; Karatekin, Ozgur; Garcia, Raphael; Carrasco, José; Garcia de Quiros, Javier; Vasseur, Hugues; Ritter, Birgit; Eubanks, Marshall; Radley, Charles; Dehant, Veronique

    2016-04-01

    Despite the successes of recent space missions (e.g., Cheng et al., 1997; Fujiwara et al., 2006), there is still no clear understanding of the asteroid internal structure(s). Depending on their size, evolution and physical properties, many different asteroid internal structure models have been suggested from completely cohesive bodies, through to rubble pile objects. The Asteroid Geophysical Explorer (AGEX), a COPINS payload selected by ESA*, will land geophysical instrument packages on the surface of Didymoon; the secondary object in the (65803) Didymos (1996 GT) binary system (Karatekin et al 2016). The instruments will characterize the asteroid surface mechanical properties and probe, for the first time, the sub-surface structure of an asteroid. AGEX will be deployed from AIM on a ballistic transfer to the asteroid surface, several days before the MASCOT-2 package. We expect that AGEX will bounce multiple times before coming to rest on the surface of the asteroid thus providing a unique opportunity to study the asteroid surface properties, perhaps at several locations, using accelerometers. Once stationary, the seismological surface-monitoring phase, using a three-axis set of geophones, can begin. The high speed DART impact will be a major seismic source on Didymoon. However, the seismic payload may also be able to perform seismological investigations using natural seismic sources such as micrometeoroid impacts (e.g., Garcia et al., 2015), thermal cracks (e.g., Delbo et al., 2014), internal quakes due to tidal forces (e.g., Richardson et al. 1998) and other geophysical processes (see Murdoch et al., 2015). We will present the expected signal characteristics of the landing and also of the natural seismic sources that may occur on Didymoon. An understanding of the amplitude and frequency content of such signals is necessary in order to design the optimal geophysical payload for small body exploration using a CubeSat platform. [1.] Cheng, A. et al., Journal of

  19. Formation of Observed Asteroid Systems by Rotational Fission

    Science.gov (United States)

    Jacobson, Seth A.; Scheeres, D. J.

    2010-05-01

    Binary asteroid systems comprise 16% of the Near-Earth asteroid (NEA) population. A proposed mechanism for creating these systems is rotational fission, observational evidence for which is being reported at this meeting (Scheeres, Pravec, et al.). We have developed a detailed simulation of this process to mimic the evolution of rubble pile asteroids spun to fission by YORP. We model the proto-binary using tri-axial ellipsoid components to capture spin-orbit coupling, apply instantaneous tidal torques to both members to model energy dissipation, and incorporate solar perturbations. After fission these binaries are located deep in their Hill sphere and their non-spherical shapes strongly couple the spin and orbital states of the bodies, transferring angular momentum and energy across the system. These systems evolve chaotically and quickly, and often reach high apoapsis radii where solar perturbations can play an important role. We find distinct evolution of the systems as a function of the mass ratio of the fissioned asteroid. For mass ratios greater than 0.2 systems cannot escape and all rapidly evolve into doubly-synchronous binaries, similar to Hermes, whose apparent lack of abundance may be due to observational bias and to rapid evolution due to the BYORP effect. For mass ratios less than 0.2 we find a number of different outcomes. First, the systems are Hill unstable and can escape from each other, forming asteroid pairs. Prior to escape, however, the secondary of a significant fraction is spun to fission, thus creating a temporary ternary system subject to three body dynamics, solar perturbations, spin-orbit coupling, and additional fission events. Resulting from our simulations we find final asteroid states that include a-synchronous binaries, high eccentricity binaries, ternary systems, and asteroid pairs - all of which are also found in the observed asteroid population. The process also predicts the creation of primaries with equatorial bulges.

  20. Asteroid flux towards circumprimary habitable zones in binary star systems: II. Dynamics

    CERN Document Server

    Bancelin, D; Bazso, A

    2015-01-01

    Secular and mean motion resonances (hearafter MMR) are effective perturbations to shape planetary systems. In binary star systems, they play a key role during the early and late phases of planetary formation as well as the dynamical stability of a planetary system. In this study, we aim to correlate the presence of orbital resonances with the rate of icy asteroids crossing the habitable zone (hearafter HZ), from a circumprimary disk of planetesimals in various binary star systems. We modelled a belt of small bodies in the inner and outer regions, respectively below and beyond the orbit of a gas giant planet. The planetesimals are equally placed around a primary G-type star and move under the gravitational influence of the two stars and the gas giant. We numerically integrated the system for 50 Myr considering various parameters for the secondary star. Its stellar type varies from a M- to F-type; its semimajor axis is either 50 au or 100 au and its eccentricity is either 0.1 or 0.3. Our simulations highlight t...

  1. Near-Sun asteroids

    Science.gov (United States)

    Emel'yanenko, V. V.

    2017-01-01

    As follows from dynamical studies, in the course of evolution, most near-Earth objects reach orbits with small perihelion distances. Changes of the asteroids in the vicinity of the Sun should play a key role in forming the physical properties, size distribution, and dynamical features of the near-Earth objects. Only seven of the discovered asteroids are currently moving along orbits with perihelion distances q orbits farther from the Sun. In this study, we found asteroids that have been recently orbiting with perihelion distances q orbits for hundreds to tens of thousands of years. To carry out astrophysical observations of such objects is a high priority.

  2. Orbital Motion in the Vicinity of the Non-collinear Equilibrium Points of a Contact Binary Asteroid

    Science.gov (United States)

    Feng, Jinglang; Noomen, Ron; Yuan, Jianping

    2015-11-01

    The orbital motion around the non-collinear equilibrium points (EPs) of a contact binary asteroid is investigated in this paper. A contact binary asteroid is an asteroid consisting of two lobes that are in physical contact. Here, it is represented by the combination of an ellipsoid and a sphere. The gravity field of the ellipsoid is approximated by a spherical harmonic expansion with terms C20 ,C22 and C40, and the sphere by a straightforward point mass model. The non-collinear EPs are linearly stable for asteroids with slow rotation rates, and become unstable as the rotation rate goes up. To study the motion around the stable EPs, a third-order analytical solution is constructed, by the Lindstedt-Poincaré (LP) method. A good agreement is found between this analytical solution and numerical integrations for the motion in the vicinity of the stable EPs. Its accuracy decreases when the orbit goes further away from the EPs and the asteroid rotates faster. For the unstable EPs, the motions around them are unstable as well. Therefore, the linear feedback control law based on low thrust is introduced to stabilize the motion and track the reference trajectory. In addition, more control force is required as any of the injection error, the amplitude of the analytical reference orbit or the rotation rate of the asteroid increases. For small orbits around the EPs, the third-order analytical solution can serve as a good reference trajectory. However, for large amplitude orbits, accurate numerical orbits are to be used as reference. This avoids an extra control force to track the less accurate third-order analytical solution.

  3. The Need for Speed in Near-Earth Asteroid Characterization

    CERN Document Server

    Galache, J L; McLeod, K K; Elvis, M

    2015-01-01

    We have used Minor Planet Center data and tools to explore the discovery circumstances and properties of the currently known population of over 10,000 NEAs, and to quantify the challenges for follow-up from ground-based telescopes. The increasing rate of discovery has grown to ~1,000/year as surveys have become more sensitive, by 1mag every ~7.5 years. However, discoveries of large (H == 4, making reacquisition more than a year following discovery difficult; for H > 22 this fraction is over 90%. We argue that rapid follow-up will be essential to characterize newly-discovered NEAs. Most new NEAs are found within 0.5mag of peak brightness and fade quickly, typically by 0.5/3.5/5mag after 1/4/6 weeks. About 80% have synodic periods of 22 NEAs that tend to return 100 times fainter. We show that for characterization to keep pace with discovery would require: Visible spectroscopy within days with a dedicated >2m telescope; long-arc astrometry, used also for phase curves, with a >4m telescope; and fast-cadence (= 4...

  4. Characterization of the near-Earth Asteroid 2002 NY40

    Science.gov (United States)

    2007-09-01

    and Vesta ; Rotational Poles and Triaxial Ellipsoid Dimensions, Icarus, 132, 80-99 – 17 – Fish, D.A., Brinicombe, A.M., & Pike, E.R. 1995, Blind...rectification of observed sistributions, Astron. J. 79, 745-754 McCarthy, D.W., Freeman, J.D., Drummond, J.D 1994, High Resolution Images of Vesta at

  5. Near-Earth Asteroid Origin for the Farmington Meteorite

    Science.gov (United States)

    Marti, K.; Mathew, K. J.

    2002-01-01

    We report nitrogen and xenon isotopic signatures in separated metal and non-magnetic phases of a catastrophically degassed L5 chondrite and discuss implications for the collisional event and the impactor. Additional information is contained in the original extended abstract.

  6. Klet Observatory – European Contribution to Detecting and Tracking of Near Earth Objects

    Directory of Open Access Journals (Sweden)

    Milos Tichy

    2012-03-01

    Full Text Available Near Earth Object (NEO research is an expanding field of astronomy. Is is important for solar system science and also for protecting human society from asteroid and comet hazard.  A near-Earth object (NEO can be defined as an asteroid or comet that has a possibility of making an approach to the Earth, or possibly even collide with it. The discovery rate of current NEO surveys reflects progressive improvement in a number of technical areas. An integral part of NEO discovery is astrometric follow-up fundamental for precise orbit computation and for the reasonable judging of future close encounters with the Earth including possible impact solutions. A wide international cooperation is fundamental for NEO research.  The Klet Observatory (South Bohemia, Czech Republic is aimed especially at the confirmation, early follow-up, long-arc follow-up and recovery of Near Earth Objects. It ranks among the world´s most prolific professional NEO follow-up programmes.  The first NEO follow-up programme started at Klet in 1993 using 0.57-reflector equipped with a small CCD camera. A fundamental upgrade was made in 2002 when the 1.06-m KLENOT telescope was put into regular operation. The KLENOT Telescope is the largest telescope in Europe used exclusively for observations of minor planets (asteroids and comets and full observing time is dedicated to the KLENOT team.  Equipment, technology, software, observing strategy and results of both the Klet Observatory NEO Project between 1993-2010 and the first phase of the KLENOT Project from March 2002 to September 2008 are presented. They consist of thousands of precise astrometric measurements of Near Earth Objects and also three newly discovered Near Earth Asteroids.  Klet Observatory NEO activities as well as our future plans fully reflect international strategies and cooperation in the field of NEO studies.

  7. Science case for the Asteroid Impact Mission (AIM): A component of the Asteroid Impact & Deflection Assessment (AIDA) mission

    Science.gov (United States)

    Michel, Patrick; Cheng, A.; Küppers, M.; Pravec, P.; Blum, J.; Delbo, M.; Green, S. F.; Rosenblatt, P.; Tsiganis, K.; Vincent, J. B.; Biele, J.; Ciarletti, V.; Hérique, A.; Ulamec, S.; Carnelli, I.; Galvez, A.; Benner, L.; Naidu, S. P.; Barnouin, O. S.; Richardson, D. C.; Rivkin, A.; Scheirich, P.; Moskovitz, N.; Thirouin, A.; Schwartz, S. R.; Campo Bagatin, A.; Yu, Y.

    2016-06-01

    The Asteroid Impact & Deflection Assessment (AIDA) mission is a joint cooperation between European and US space agencies that consists of two separate and independent spacecraft that will be launched to a binary asteroid system, the near-Earth asteroid Didymos, to test the kinetic impactor technique to deflect an asteroid. The European Asteroid Impact Mission (AIM) is set to rendezvous with the asteroid system to fully characterize the smaller of the two binary components a few months prior to the impact by the US Double Asteroid Redirection Test (DART) spacecraft. AIM is a unique mission as it will be the first time that a spacecraft will investigate the surface, subsurface, and internal properties of a small binary near-Earth asteroid. In addition it will perform various important technology demonstrations that can serve other space missions. The knowledge obtained by this mission will have great implications for our understanding of the history of the Solar System. Having direct information on the surface and internal properties of small asteroids will allow us to understand how the various processes they undergo work and transform these small bodies as well as, for this particular case, how a binary system forms. Making these measurements from up close and comparing them with ground-based data from telescopes will also allow us to calibrate remote observations and improve our data interpretation of other systems. With DART, thanks to the characterization of the target by AIM, the mission will be the first fully documented impact experiment at asteroid scale, which will include the characterization of the target's properties and the outcome of the impact. AIDA will thus offer a great opportunity to test and refine our understanding and models at the actual scale of an asteroid, and to check whether the current extrapolations of material strength from laboratory-scale targets to the scale of AIDA's target are valid. Moreover, it will offer a first check of the

  8. NEOWISE Observations of Near-Earth Objects: Preliminary Results

    CERN Document Server

    Mainzer, A; Bauer, J; Masiero, J; McMillan, R S; Cutri, R M; Walker, R; Wright, E; Eisenhardt, P; Tholen, D J; Spahr, T; Jedicke, R; Denneau, L; DeBaun, E; Elsbury, D; Gautier, T; Gomillion, S; Hand, E; Mo, W; Watkins, J; Wilkins, A; Bryngelson, G L; Molina, A Del Pino; Desai, S; Camus, M Go'mez; Hidalgo, S L; Konstantopoulos, I; Larsen, J A; Maleszewski, C; Malkan, M A; Mauduit, J -C; Mullan, B L; Olszewski, E W; Pforr, J; Saro, A; Scotti, J V; Wasserman, L H

    2011-01-01

    With the NEOWISE portion of the \\emph{Wide-field Infrared Survey Explorer} (WISE) project, we have carried out a highly uniform survey of the near-Earth object (NEO) population at thermal infrared wavelengths ranging from 3 to 22 $\\mu$m, allowing us to refine estimates of their numbers, sizes, and albedos. The NEOWISE survey detected NEOs the same way whether they were previously known or not, subject to the availability of ground-based follow-up observations, resulting in the discovery of more than 130 new NEOs. The survey's uniformity in sensitivity, observing cadence, and image quality have permitted extrapolation of the 428 near-Earth asteroids (NEAs) detected by NEOWISE during the fully cryogenic portion of the WISE mission to the larger population. We find that there are 981$\\pm$19 NEAs larger than 1 km and 20,500$\\pm$3000 NEAs larger than 100 m. We show that the Spaceguard goal of detecting 90% of all 1 km NEAs has been met, and that the cumulative size distribution is best represented by a broken powe...

  9. The global impact distribution of Near-Earth objects

    Science.gov (United States)

    Rumpf, Clemens; Lewis, Hugh G.; Atkinson, Peter M.

    2016-02-01

    Asteroids that could collide with the Earth are listed on the publicly available Near-Earth object (NEO) hazard web sites maintained by the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA). The impact probability distribution of 69 potentially threatening NEOs from these lists that produce 261 dynamically distinct impact instances, or Virtual Impactors (VIs), were calculated using the Asteroid Risk Mitigation and Optimization Research (ARMOR) tool in conjunction with OrbFit. ARMOR projected the impact probability of each VI onto the surface of the Earth as a spatial probability distribution. The projection considers orbit solution accuracy and the global impact probability. The method of ARMOR is introduced and the tool is validated against two asteroid-Earth collision cases with objects 2008 TC3 and 2014 AA. In the analysis, the natural distribution of impact corridors is contrasted against the impact probability distribution to evaluate the distributions' conformity with the uniform impact distribution assumption. The distribution of impact corridors is based on the NEO population and orbital mechanics. The analysis shows that the distribution of impact corridors matches the common assumption of uniform impact distribution and the result extends the evidence base for the uniform assumption from qualitative analysis of historic impact events into the future in a quantitative way. This finding is confirmed in a parallel analysis of impact points belonging to a synthetic population of 10,006 VIs. Taking into account the impact probabilities introduced significant variation into the results and the impact probability distribution, consequently, deviates markedly from uniformity. The concept of impact probabilities is a product of the asteroid observation and orbit determination technique and, thus, represents a man-made component that is largely disconnected from natural processes. It is important to consider impact

  10. Asteroid spin-up fission systems

    Science.gov (United States)

    Pravec, P.

    2014-07-01

    Among asteroids smaller than about 15 km in diameter, there is a population of binary and multiple asteroid systems that show characteristics strongly suggesting their formation by spin-up fission. I will review the current observational data we have on the systems and compare them with predictions from theories of formation of asteroid systems. I will show that the best explanation of their observed properties is provided by the theory of fission of cohesionless (rubble-pile) asteroids spun up to the critical spin frequency by the YORP effect. Observed asteroid systems are of two kinds: bound and unbound. Bound asteroid systems typically consist of a larger primary and one or two smaller satellites. Unbound systems consist of two asteroids orbiting the Sun on highly similar orbits, again with one being typically larger (primary) and the other being smaller (secondary). These two groups are not exclusive; there exist systems with one or two bound and an unbound secondary. Our current sample consists of 133 bound asteroid systems (binaries or triples) with primary sizes between 0.12 and 13 km and of 178 asteroid pairs with similar primary sizes. Bound systems have been observed in heliocentric orbits from near the Earth to the outer main belt, while asteroid pairs are recognizable only in the main belt where their orbits are only slowly dispersed so the pairs can be identified for up to 2 Myr after formation. The leading observational techniques for discovery and characterization of asteroid systems are radar imagery (for near-Earth asteroid systems) and lightcurve photometry (for main-belt ones). The observed characteristics of asteroid systems suggesting their formation by rotational fission of parent rubble-pile asteroids after being spun up by the YORP effect are as follows. The angular momentum content of binary asteroids is close to critical. The orientations of satellite orbits are non-random; the orbital poles concentrate near the obliquities of 0 and 180

  11. Searching for the first Near-Earth Object family

    CERN Document Server

    Schunova, Eva; Jedicke, Robert; Gronchi, Giovanni; Wainscoat, Richard; Abe, Shinsuke; 10.1016/j.icarus.2012.06.042

    2012-01-01

    We report on our search for genetically related asteroids amongst the near-Earth object (NEO) population - families of NEOs akin to the well known main belt asteroid families. We used the technique proposed by Fu et al. (2005) supplemented with a detailed analysis of the statistical significance of the detected clusters. Their significance was assessed by comparison to identical searches performed on 1,000 'fuzzy-real' NEO orbit distribution models that we developed for this purpose. The family-free 'fuzzy-real' NEO models maintain both the micro and macro distribution of 5 orbital elements (ignoring the mean anomaly). Three clusters were identified that contain four or more NEOs but none of them are statistically significant at \\geq 3{\\sigma}. The most statistically significant cluster at the \\sim 2{\\sigma} level contains 4 objects with H < 20 and all members have long observational arcs and concomitant good orbital elements. Despite the low statistical significance we performed several other tests on the...

  12. Dormant Comets Among the Near-Earth Object Population: A Meteor-Based Survey

    CERN Document Server

    Ye, Quan-Zhi; Pokorný, Petr

    2016-01-01

    Dormant comets in the near-Earth object (NEO) population are thought to be involved in the terrestrial accretion of water and organic materials. Identification of dormant comets is difficult as they are observationally indistinguishable from their asteroidal counterparts, however they may have produced dust during their final active stages which potentially are detectable today as weak meteor showers at the Earth. Here we present the result of a reconnaissance survey looking for dormant comets using 13~567~542 meteor orbits measured by the Canadian Meteor Orbit Radar (CMOR). We simulate the dynamical evolution of the hypothetical meteoroid streams originated from 407 near-Earth asteroids in cometary orbits (NEACOs) that resemble orbital characteristics of Jupiter-family comets (JFCs). Out of the 44 hypothetical showers that are predicted to be detectable by CMOR, we identify 5 positive detections that are statistically unlikely to be chance associations, including 3 previously known associations. This transla...

  13. The Near-Earth Plasma Environment

    Science.gov (United States)

    Pfaff, Robert F., Jr.

    2012-01-01

    An overview of the plasma environment near the earth is provided. We describe how the near-earth plasma is formed, including photo-ionization from solar photons and impact ionization at high latitudes from energetic particles. We review the fundamental characteristics of the earth's plasma environment, with emphasis on the ionosphere and its interactions with the extended neutral atmosphere. Important processes that control ionospheric physics at low, middle, and high latitudes are discussed. The general dynamics and morphology of the ionized gas at mid- and low-latitudes are described including electrodynamic contributions from wind-driven dynamos, tides, and planetary-scale waves. The unique properties of the near-earth plasma and its associated currents at high latitudes are shown to depend on precipitating auroral charged particles and strong electric fields which map earthward from the magnetosphere. The upper atmosphere is shown to have profound effects on the transfer of energy and momentum between the high-latitude plasma and the neutral constituents. The article concludes with a discussion of how the near-earth plasma responds to magnetic storms associated with solar disturbances.

  14. Identifying meteorite source regions through near-Earth object spectroscopy

    Science.gov (United States)

    Thomas, Cristina A.; Binzel, Richard P.

    2010-02-01

    By virtue of their landing on Earth, meteorites reside in near-Earth object (NEO) orbits prior to their arrival. Thus the population of observable NEOs, in principle, gives important representation of meteorite source bodies. By linking meteorites to NEOs, and linking NEOs to their most likely main-belt source locations, we seek to gain insight into the original Solar System formation locations for different meteorite classes. To forge possible links between meteorites and NEOs, we have developed a three dimensional method for quantitative comparisons between laboratory measurements of meteorites and telescopic measurements of near-Earth objects. We utilize meteorite spectra from the Reflectance Experiment Laboratory (RELAB) database and NEO data from the SpeX instrument on the NASA Infrared Telescope Facility (IRTF). Using the Modified Gaussian Model (MGM) as a mathematical tool, we treat asteroid and meteorite spectra identically in the calculation of 1-μm and 2-μm Geometric Band Centers and their Band Area Ratios (BARs). Using these identical numerical parameters we quantitatively compare the spectral properties of S-, Sq-, Q- and V-type NEOs with the spectral properties of the meteorites in four classes: H, L, LL and HED. For each NEO spectrum, we assign a set of probabilities for it being related to each of these four meteorite classes. Our NEO-meteorite correlation probabilities are then convolved with NEO-source region probabilities to yield a final set of meteorite-source region correlations. While the ν6 resonance dominates the delivery for all four meteorite classes, an excess (significant at the 2.1-sigma level) source region signature is found for the H chondrites through the 3:1 mean motion resonance. This results suggest an H chondrite source with a higher than average delivery preference through the 3:1 resonance. A 3:1 resonance H chondrite source region is consistent with the short cosmic ray exposure ages known for H chondrites.

  15. Thermal-Infrared Surveys of Near-Earth Object Diameters and Albedos with Spitzer and IRTF/MIRSI

    NARCIS (Netherlands)

    Mommert, Michael; Trilling, David; Hora, Joseph L.; Chesley, Steven; Emery, Josh; Fazio, Giovanni; Harris, Alan W.; Moskovitz, Nick; Mueller, Michael; Smith, Howard

    2015-01-01

    More than 12000 Near-Earth Objects (NEOs) have been discovered over the past few decades and current discovery surveys find on average 4 new NEOs every night. In comparison to asteroid discovery, the physical characterization of NEOs lags far behind: measured diameters and albedos exist only for rou

  16. AIDA: the Asteroid Impact & Deflection Assessment mission

    Science.gov (United States)

    Vincent, Jean-Baptiste

    2016-07-01

    The Asteroid Impact & Deflection Assessment (AIDA) mission is a joint cooperation between European and US space agencies that consists of two separate and independent spacecraft that will be launched to a binary asteroid system, the near-Earth asteroid Didymos, to assess the possibility of deflecting an asteroid trajectory by using a kinetic impactor. The European Asteroid Impact Mission (AIM) is under Phase A/B1 study at ESA from March 2015 until summer 2016. AIM is set to rendez-vous with the asteroid system a few months prior to the impact by the US Double Asteroid Redirection Test (DART) spacecraft to fully characterize the smaller of the two binary components. AIM is a unique mission as it will be the first time that a spacecraft will investigate the surface, subsurface, and internal properties of a small binary near Earth asteroid. In addition it will perform various important technology demonstrations that can serve other space missions: AIM will release a set of CubeSats in deep space and a lander on the surface of the smaller asteroid and for the first time, deep-space inter-satellite linking will be demonstrated between the main spacecraft, the CubeSats, and the lander, and data will also be transmitted from interplanetary space to Earth by a laser communication system. The knowledge obtained by this mission will have great implications for our understanding of the history of the Solar System. Small asteroids are believed to result from collisions and other processes (e.g., spinup, shaking) that made them what they are now. Having direct information on their surface and internal properties will allow us to understand how these processes work and transform these small bodies as well as, for this particular case, how a binary system forms. So far, our understanding of the collisional process and the validation of numerical simulations of the impact process rely on impact experiments at laboratory scales. With DART, thanks to the characterization of the

  17. A new non-convex model of the binary asteroid (809) Lundia obtained with the SAGE modelling technique

    Science.gov (United States)

    Bartczak, P.; Kryszczyńska, A.; Dudziński, G.; Polińska, M.; Colas, F.; Vachier, F.; Marciniak, A.; Pollock, J.; Apostolovska, G.; Santana-Ros, T.; Hirsch, R.; Dimitrow, W.; Murawiecka, M.; Wietrzycka, P.; Nadolny, J.

    2017-10-01

    We present a new non-convex model of the binary asteroid (809) Lundia. A SAGE (Shaping Asteroids with Genetic Evolution) method using disc-integrated photometry only was used for deriving physical parameters of this binary system. The model of (809) Lundia improves former system's pole solution and gives the ecliptic coordinates of the orbit pole - λ = 122°, β = 22°, σ = ±5° - and the orbital period of 15.415 74 ± 0.000 01 h. For scaling our results, we used an effective diameter (Deff) of 9.6 ± 1.1 km obtained from Spitzer observations. The non-convex shape description of the components permitted a refined calculation of the components' volumes, leading to a density estimation of 2.5 ± 0.2 g cm-3 and a macroporosity of 13-23 per cent. The intermediate-scale features of the model may also offer new clues on the components' origin and evolution.

  18. A new non-convex model of the binary asteroid 90 Antiope obtained with the SAGE modelling technique

    Science.gov (United States)

    Bartczak, P.; Michałowski, T.; Santana-Ros, T.; Dudziński, G.

    2014-09-01

    We present a new non-convex model of the 90 Antiope binary asteroid, derived with a modified version of the Shaping Asteroids with Genetic Evolution (SAGE) method using disc-integrated photometry only. A new variant of the SAGE algorithm capable of deriving models of binary systems is described. The model of 90 Antiope confirms the system's pole solution (λ = 199°, β = 38°, σ = ±5°) and the orbital period (16.505 046 ± 0.000 005 h). A comparison between the stellar occultation chords obtained during the 2011 occultation and the projected shape solution has been used to scale the model. The resulting scaled model allowed us to obtain the equivalent radii (R1 = 40.4 ± 0.9 km and R2 = 40.2 ± 0.9 km) and the distance between the two system components (176 ± 4 km), leading to a total system mass of (9.14 ± 0.62) · 1017 kg. The non-convex shape description of the components permitted a refined calculation of the components' volumes, leading to a density estimation of 1.67 ± 0.23 g cm-3. The intermediate-scale features of the model may also offer new clues on the components' origin and evolution.

  19. A new non-convex model of the binary asteroid 90 Antiope obtained with the SAGE modelling technique

    CERN Document Server

    Bartczak, P; Santana-Ros, T; Dudziński, G

    2014-01-01

    We present a new non-convex model of the 90 Antiope binary asteroid, derived with a modified version of the SAGE (Shaping Asteroids with Genetic Evolution) method using disk-integrated photometry only. A new variant of the SAGE algorithm capable of deriving models of binary systems is described. The model of 90 Antiope confirms the system's pole solution ($\\lambda=199^{\\circ}$, $\\beta=38^{\\circ}$, $\\sigma=\\pm5^{\\circ}$) and the orbital period ($16.505046 \\pm 0.000005$ h). A comparison between the stellar occultation chords obtained during the 2011 occultation and the projected shape solution has been used to scale the model. The resulting scaled model allowed us to obtain the equivalent radii ($R_{1}=40.4\\pm0.9$ km and $R_{2}=40.2\\pm0.9$ km) and the distance between the two system components ($176\\pm4$ km), leading to a total system mass of ($9.14\\pm0.62$)$\\cdot10^{17}$ kg. The non-convex shape description of the components permitted a refined calculation of the components' volumes, leading to a density estim...

  20. NASA's Asteroid Redirect Mission (ARM)

    Science.gov (United States)

    Abell, P. A.; Mazanek, D. D.; Reeves, D. M.; Chodas, P. W.; Gates, M. M.; Johnson, L. N.; Ticker, R. L.

    2017-01-01

    Mission Description and Objectives: NASA's Asteroid Redirect Mission (ARM) consists of two mission segments: 1) the Asteroid Redirect Robotic Mission (ARRM), a robotic mission to visit a large (greater than approximately 100 meters diameter) near-Earth asteroid (NEA), collect a multi-ton boulder from its surface along with regolith samples, and return the asteroidal material to a stable orbit around the Moon; and 2) the Asteroid Redirect Crewed Mission (ARCM), in which astronauts will explore and investigate the boulder and return to Earth with samples. The ARRM is currently planned to launch at the end of 2021 and the ARCM is scheduled for late 2026.

  1. Dormant comets among the near-Earth object population: a meteor-based survey

    Science.gov (United States)

    Ye, Quan-Zhi; Brown, Peter G.; Pokorný, Petr

    2016-11-01

    Dormant comets in the near-Earth object (NEO) population are thought to be involved in the terrestrial accretion of water and organic materials. Identification of dormant comets is difficult as they are observationally indistinguishable from their asteroidal counterparts, however, they may have produced dust during their final active stages which potentially are detectable today as weak meteor showers at the Earth. Here we present the result of a reconnaissance survey looking for dormant comets using 13 567 542 meteor orbits measured by the Canadian Meteor Orbit Radar (CMOR). We simulate the dynamical evolution of the hypothetical meteoroid streams originated from 407 near-Earth asteroids in cometary orbits that resemble orbital characteristics of Jupiter-family comets (JFCs). Out of the 44 hypothetical showers that are predicted to be detectable by CMOR, we identify five positive detections that are statistically unlikely to be chance associations, including three previously known associations. This translates to a lower limit to the dormant comet fraction of 2.0 ± 1.7 per cent in the NEO population and a dormancy rate of ˜10-5 yr-1 per comet. The low dormancy rate confirms disruption and dynamical removal as the dominant end state for near-Earth JFCs. We also predict the existence of a significant number of meteoroid streams whose parents have already been disrupted or dynamically removed.

  2. NEOCam: The Near-Earth Object Camera

    Science.gov (United States)

    Mainzer, Amy K.; NEOCam Science Team

    2016-10-01

    The Near-Earth Object Camera (NEOCam) is a Discovery mission in Phase A study designed to carry out a large-scale survey of the inner solar system's minor planets. Its primary science objectives are to understand the origins of the solar system's small bodies and the processes that evolved them into their present state. The mission will also characterize the impact hazard from near-Earth objects as well as rare populations such as Earth Trojans and interior-to-Earth objects. In the process, NEOCam can identify targets for future robotic or human exploration. Using a 50 cm telescope operating in two infrared wavelengths (4-5.2 and 6-10 um), the mission is expected to detect and characterize close to 100,000 NEOs and thousands of comets. By achieving high survey completeness in the main belt down to kilometer-scale objects, NEOCam-derived size and albedo distributions can be directly compared to those of the NEOs. The hypotheses that small, dark NEOs and comets are preferentially disrupted at low perihelia can be tested by searching for correlations between size, orbital elements, and albedos. NEOCam's Sun-Earth L1 Lagrange point halo orbit enables a large instantaneous field of regard with a view of low solar elongations, high data rates, and a cold thermal environment. Like its predecessor, WISE/NEOWISE, candidate minor planet detections will be rapidly disseminated to the community via the Minor Planet Center. NEOCam images, source databases, and tables of derived physical properties will be delivered to the community via NASA's Infrared Science Archive and PDS.

  3. Asteroid exploration and utilization

    Science.gov (United States)

    Radovich, Brian M.; Carlson, Alan E.; Date, Medha D.; Duarte, Manny G.; Erian, Neil F.; Gafka, George K.; Kappler, Peter H.; Patano, Scott J.; Perez, Martin; Ponce, Edgar

    1992-01-01

    The Earth is nearing depletion of its natural resources at a time when human beings are rapidly expanding the frontiers of space. The resources possessed by asteroids have enormous potential for aiding and enhancing human space exploration as well as life on Earth. Project STONER (Systematic Transfer of Near Earth Resources) is based on mining an asteroid and transporting raw materials back to Earth. The asteroid explorer/sample return mission is designed in the context of both scenarios and is the first phase of a long range plan for humans to utilize asteroid resources. Project STONER is divided into two parts: asteroid selection and explorer spacecraft design. The spacecraft design team is responsible for the selection and integration of the subsystems: GNC, communications, automation, propulsion, power, structures, thermal systems, scientific instruments, and mechanisms used on the surface to retrieve and store asteroid regolith. The sample return mission scenario consists of eight primary phases that are critical to the mission.

  4. Thermal inertia of eclipsing binary asteroids : the role of component shape

    NARCIS (Netherlands)

    Mueller, Michael; van de Weijgaert, Marlies

    2015-01-01

    Thermal inertia controls the temperature distribution on asteroid surfaces. This is of crucial importance to the Yarkovsky effect and for the planning of spacecraft operations on or near the surface. Additionally, thermal inertia is a sensitive indicator for regolith structure.A uniquely direct way

  5. Thermal inertia of eclipsing binary asteroids: the role of component shape

    NARCIS (Netherlands)

    Mueller, Michael; van de Weijgaert, Marlies

    2015-01-01

    Thermal inertia controls the temperature distribution on asteroid surfaces. This is of crucial importance to the Yarkovsky effect and for the planning of spacecraft operations on or near the surface. Additionally, thermal inertia is a sensitive indicator for regolith structure.A uniquely direct way

  6. A mission concept for a Grand Tour of Multiple Asteroid Systems

    Science.gov (United States)

    Marchis, F.; Dankanich, J.; Tricarico, P.; Bellerose, J.

    2009-12-01

    In 1993, the Galileo spacecraft imaged the first companion of asteroid, Dactyl orbiting 243 Ida, a main-belt asteroid. Since then, discoveries have been accumulated thanks to the development of high angular resolution imaging on ground-based telescopes (adaptive optics), radar observations and accurate photometric light curve measurements. To date, 180 companions of small solar system bodies (SSSBs) are known in various populations, including 100 in the asteroid main belt, 33 Near Earth Asteroids, 4 Jupiter-Trojan asteroids and 44 in the Kuiper Belt. Multiple Asteroids have been shown to be complex worlds in their own with a wide range of morphologies, dynamical histories, and structural evolution. To the exception of 243 Ida, no spacecraft has visited any of them. Investigating binary asteroid systems can verify and validate current theories on their formation and on the influence of the sun in their formation (YORP effect) and evolution (space weathering). In particular, assessing the origin of the secondary satellite, if it is of common origin or capture, can provide clue of their formation. To a larger extend, the determination of their nature, scenario formation and evolution are key to understand how planet formation occurred but also to understand i) the population and compositional structure of the SSSB today ii) how the dynamics and collisions modify this structure over time iii) what the physical properties of asteroids are (density, porosity) iv) how the surface modification processes affect our ability to determine this structure (e.g. space weathering). In addition, being able to study these properties on closeby asteroids will give a relative scale accounting for the sizes, shape, rotation periods and cratering rate of these small and young bodies. In the framework of the NASA Discovery program, we propose a mission consisting of a Grand Tour of several multiple asteroid systems, including the flyby of a near earth binary asteroid and the rendezvous

  7. The Tunguska Event and the History of Near-Earth Objects

    Science.gov (United States)

    Yeomans, Donald K.

    2006-12-01

    At 7:17 o’clock in the morning of June 30, 1908 a 60 meter-sized asteroid exploded over the Tunguska region of Russian Siberia, leveling trees for some 22 miles from the blast center. Today, the Tunguska blast is used as the only example of a witnessed and documented Earth impact by a substantial near-Earth asteroid. Although striking Earth with the impact energy of 15 mega tons of TNT, the Tunguska event had very little effect upon contemporary views of Earth impacts by neighboring comets and asteroids. While Edmond Halley had pointed out in 1694 that comets could strike the Earth with catastrophic consequences, the far more numerous potentially hazardous asteroids were unknown until the discovery of asteroid 1862 Apollo in 1932 the first asteroid found to actually cross the Earth’s orbit. It was only in the second half of the last century when astronomers generally believed that the moon’s craters were largely due to asteroid impacts rather than volcanoes and more recent still before the realization that there are likely more than 20,000 asteroids large enough to cause serious consequences to Earth’s surface and close enough to Earth’s orbit to pose a near-term threat. The Tunguska event of 1908 could have been used to lead toward these conclusions much earlier but this was not to be the case because of the lack of information on this remote event, the initial unwillingness of most professional astronomers to attribute the lunar craters to impact events and because it was realized only recently that the Earth’s neighborhood is crowded with potential asteroid impactors.

  8. Asteroid Detection Results Using the Space Surveillance Telescope

    Science.gov (United States)

    2015-10-18

    Distribution Statement A: Approved for public release, distribution unlimited. Asteroid Detection Results Using the Space Surveillance Telescope...USA ABSTRACT From 1998-2013, MIT Lincoln Laboratory operated a highly successful near-Earth asteroid search program using...two 1-m optical telescopes located at the MIT Lincoln Laboratory Experimental Test Site (ETS) in Socorro, N.M. In 2014, the Lincoln Near-Earth Asteroid

  9. New determination of the size and bulk density of the binary asteroid 22 Kalliope from observations of mutual eclipses

    CERN Document Server

    Descamps, P; Pollock, J; Berthier, J; Vachier, F; Birlan, M; Kaasalainen, M; Harris, A W; Wong, M; Romanishin, W; Cooper, E M; Kettner, K A; Wiggins, P; Kryszczynska, A; Polinska, M; Colliac, J -F; Devyatkin, A; Verestchagina, I; Gorshanov, D

    2007-01-01

    In 2007, the M-type asteroid 22 Kalliope reached one of its annual equinoxes. As a consequence, its small satellite Linus orbiting in the equatorial plane underwent a season of mutual eclipses. A dedicated international campaign of observations was organized in order to study several of these scarce events. In this paper we present a summary of the observations and a comprehensive analysis based on a global model of a binary system in mutual eclipse. One of the most significant results is the derivation of a size for Kalliope of 156 +/- 4km, 11% smaller than its IRAS size. As to the diameter of Linus, it is estimated to 28+/-2 km. This shortening of Kalliope is confirmed by the interpretation of earlier observations, such as adaptive optics imaging and those of the stellar occultation of 2006 November, 7. Kalliope appears now as a much more common object with a bulk density of 4.1+/-0.3g/cm3 and a macroscopic porosity of ~20-30% typical of that measured for well-known binary main belt systems. Furthermore, we...

  10. Orbital Simulations on Deflecting Near-Earth Objects by Directed Energy

    OpenAIRE

    Zhang, Qicheng; Walsh, Kevin J.; Melis, Carl; Hughes, Gary B.; Lubin, Philip M.

    2016-01-01

    Laser ablation of a Near-Earth Object (NEO) on a collision course with Earth produces a cloud of ejecta which exerts a thrust on the NEO, deflecting it from its original trajectory. Ablation may be performed from afar by illuminating an Earth-targeting asteroid or comet with a stand-off "DE- STAR" system consisting of a large phased-array laser in Earth orbit. Alternatively, a much smaller stand-on "DE-STARLITE" system may travel alongside the target, slowly deflecting it from nearby over a l...

  11. Mode-locked Lasers Applied to Deflecting a Near Earth Object on Collision Course with Earth

    CERN Document Server

    Fork, Richard; Burgess, Luke; Bergstue, Grant

    2013-01-01

    We consider synchronized trains of sub-picosecond pulses generated by mode-locked lasers applied to deflection of near Earth objects (NEO) on collision course with Earth. Our method is designed to avoid a predicted collision of the NEO with Earth by at least the diameter of Earth. We estimate deflecting a 10,000 MT NEO, such as the asteroid which struck Earth near Chelyabinsk, Russia to be feasible within several months using average power in the ten kilowatt range. We see this deflection method as scalable to larger NEO to a degree not possible using continuous laser systems.

  12. Optimal Fragmentation and Dispersion of Hazardous Near-Earth Objects

    Science.gov (United States)

    Wie, Bong

    2012-01-01

    The complex problem of protecting the Earth from the possibility of a catastrophic impact by a hazardous near-Earth object (NEO) has been recently reassessed in [1]. In a letter on NEOs from the White House Office of Science and Technology Policy (OSTP) to the U.S. Senate and Congress in 2010, the White House OSTP strongly recommended that NASA take the lead in conducting research activities for NEO detection, characterization, and deflection technologies. Furthermore, President Obama's new National Space Policy specifically directs NASA to "pursue capabilities, in cooperation with other departments, agencies, and commercial partners, to detect, track, catalog, and characterize NEOs to reduce the risk of harm to humans from an unexpected impact on our planet." The Planetary Defense Task Force of the NASA Advisory Council also recommended that the NASA Office of the Chief Technologist (OCT) begin efforts to investigate asteroid deflection techniques. With national interest growing in the United States, the NEO threat detection and mitigation problem was recently identified as one of NASA's Space Technology Grand Challenges. An innovative solution to NASA's NEO Impact Threat Mitigation Grand Challenge problem was developed through a NIAC Phase I study (9/16/11 - 9/15/12), and it will be further investigated for a NIAC Phase II study (9/10/12 - 9/9/14). Various NEO deflection technologies, including nuclear explosions, kinetic impactors, and slow-pull gravity tractors, have been proposed and examined during the past two decades. Still, there is no consensus on how to reliably deflect or disrupt hazardous NEOs in a timely manner. It is expected that the most probable mission scenarios will have a mission lead time much shorter than 10 years, so the use of nuclear explosives becomes the most feasible method for planetary defense. Direct intercept missions with a short warning time will result in arrival closing velocities of 10-30 kilometers per second with respect to

  13. Physical characterization of the near-Earth object population

    Science.gov (United States)

    Ieva, S.; Dotto, E.; Mazzotta Epifani, E.; Perna, D.; Perozzi, E.; Micheli, M.

    2017-08-01

    The Near-Earth Object (NEO) population, being the remnants of the building blocks that originally formed our solar system, allows us to understand the initial conditions that were present in the protosolar nebula. Its investigation can provide crucial information on the origin and early evolution of the solar system, and shed light on the delivery of water and organic-rich material to the early Earth. Furthermore, the possible impact of NEOs poses a serious hazard to our planet. There is an urgent need to undertake a comprehensive physical characterization of the NEO population, particularly for the ones with the higher likelihood of catastrophic impact with the Earth. One of the main aims of the NEOShield-2 project (2015-2017), financed by the European Commission in the framework of the HORIZON 2020 program, is to undertake an extensive observational campaign and provide a physical and compositional characterization for a large number of NEOs in the < 300 m size range, retrieving in particular their mitigation-relevant properties (size, shape, albedo, diameter, composition, internal structure, ...) in order to design impact mitigation missions and assess the consequences of an impact on Earth. We carried out visible photometric measurements for a sample of 158 uncharacterized NEOs. We also made use of visible and near-infrared spectroscopy to assess NEO composition and perform a mineralogical analysis. We found that carbonaceous C-complex asteroids deserve a special attention, since their physical structure ( e.g., primitive nature, porosity) and their orbital parameters (mainly the inclination) make at the moment challenging the design of a successful mitigation strategy. Indeed, the most advanced mitigation technique (the kinetic impactor) is less effective on these bodies, and the high inclination of some possible impactors require a launch vehicle capability beyond the one currently available.

  14. Threat Mitigation: The Asteroid Tugboat

    CERN Document Server

    Schweickart, R; Durda, D; Hut, P; Chapman, Clark; Durda, Dan; Hut, Piet; Schweickart, Russell

    2006-01-01

    The Asteroid Tugboat (AT) is a fully controlled asteroid deflection concept using a robotic spacecraft powered by a high efficiency, electric propulsion system (ion or plasma) which docks with and attaches to the asteroid, conducts preliminary operations, and then thrusts continuously parallel to the asteroid velocity vector until the desired velocity change is achieved. Based on early warning, provided by ground tracking and orbit prediction, it would be deployed a decade or more prior to a potential impact. On completion of the initial rendezvous with the near-Earth object (NEO) the AT would first reduce the uncertainty in the orbit of the asteroid via Earth tracking of its radio transponder while it is station keeping with the asteroid. If on analysis of tracking data a deflection is required the AT would execute a reconnaissance phase collecting and processing information about the physical characteristics of the asteroid to support subsequent operations. The AT would then dock at the appropriate pole (i....

  15. Close Approaches of Potentially Hazardous Asteroids during Two Centuries

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Asteroids are the most important small bodies in the solar system and the near-earth asteroids (NEAs) are of especial concern to the world. The reasonis that they will make close approaches to the earth in the near future. We usea reasonable dynamical model and an efficient computing method to calculate the orbits of over 160 Potentially Hazardous Asteroids (PHAs) for two centuries.

  16. The Double Asteroid Redirection Test in the AIDA Project

    Science.gov (United States)

    Cheng, Andrew; Rivkin, Andrew; Michel, Patrick

    2016-04-01

    The Asteroid Impact & Deflection Assessment (AIDA) mission will be the first space experiment to demonstrate asteroid impact hazard mitigation by using a kinetic impactor. AIDA is a joint ESA-NASA cooperative project, that includes the ESA Asteroid Impact Mission (AIM) rendezvous mission and the NASA Double Asteroid Redirection Test (DART) mission. The AIDA target is the near-Earth binary asteroid 65803 Didymos, which will make an unusually close approach to Earth in October, 2022. The ~300-kg DART spacecraft is designed to impact the Didymos secondary at 7 km/s and demonstrate the ability to modify its trajectory through momentum transfer. DART and AIM are currently Phase A studies supported by NASA and ESA respectively. The primary goals of AIDA are (1) perform a full-scale demonstration of the spacecraft kinetic impact technique for deflection of an asteroid, by targeting an object larger than ~100 m and large enough to qualify as a Potentially Hazardous Asteroid; (2) measure the resulting asteroid deflection, by targeting the secondary member of a binary NEO and measuring the period change of the binary orbit; (3) understand the hyper-velocity collision effects on an asteroid, including the long-term dynamics of impact ejecta; and validate models for momentum transfer in asteroid impacts, based on measured physical properties of the asteroid surface and sub-surface. The primary DART objectives are to demonstrate a hyper-velocity impact on the Didymos moon and to determine the resulting deflection from ground-based observatories. The DART impact on the Didymos secondary will cause a measurable change in the orbital period of the binary. Supporting Earth-based optical and radar observations and numerical simulation studies are an integral part of the DART mission. The baseline DART mission launches in December, 2020 to impact the Didymos secondary in September, 2022. There are multiple launch opportunities for DART leading to impact around the 2022 Didymos close

  17. Continued activity in P/2013 P5 PANSTARRS. Unexpected comet, rotational break-up, or rubbing binary asteroid?

    Science.gov (United States)

    Hainaut, O. R.; Boehnhardt, H.; Snodgrass, C.; Meech, K. J.; Deller, J.; Gillon, M.; Jehin, E.; Kuehrt, E.; Lowry, S. C.; Manfroid, J.; Micheli, M.; Mottola, S.; Opitom, C.; Vincent, J.-B.; Wainscoat, R.

    2014-03-01

    The object P/2013 P5 PANSTARRS was discovered in August 2013, displaying a cometary tail, but its orbital elements indicated that it was a typical member of the inner asteroid main belt. We monitored the object from 2013 August 30 until 2013 October 05 using the CFHT 3.6 m telescope (Mauna Kea, HI), the NTT (ESO, La Silla), the CA 1.23 m telescope (Calar Alto), the Perkins 1.8m (Lowell) and the 0.6 m TRAPPIST telescope (La Silla). We measured its nuclear radius to be r ≲ 0.25-0.29 km, and its colours g' - r' = 0.58 ± 0.05 and r' - i' = 0.23 ± 0.06, typical for an S-class asteroid, as expected for an object in the inner asteroid belt and in the vicinity of the Flora collisional family. We failed to detect any rotational light curve with an amplitude <0.05 mag and a double-peaked rotation period <20 h. The evolution of the tail during the observations was as expected from a dust tail. A detailed Finson-Probstein analysis of deep images acquired with the NTT in early September and with the CFHT in late September indicated that the object was active since at least late January 2013 until the time of the latest observations in 2013 September, with at least two peaks of activity around 2013 June 14 ± 10 d and 2013 July 22 ± 3 d. The changes of activity level and the activity peaks were extremely sharp and short, shorter than the temporal resolution of our observations (~1 d). The dust distribution was similar during these two events, with dust grains covering at least the 1-1000 μm range. The total mass ejected in grains <1 mm was estimated to be 3.0 × 106 kg and 2.6 × 107 kg around the two activity peaks. Rotational disruption cannot be ruled out as the cause of the dust ejection. We also propose that the components of a contact binary might gently rub and produce the observed emission. Volatile sublimation might also explain what appears as cometary activity over a period of 8 months. However, while main belt comets best explained by ice sublimation are found

  18. Research Status of the Near-Earth Asteroids’ Hazard and Mitigation%近地小行星威胁与防御研究现状

    Institute of Scientific and Technical Information of China (English)

    马鹏斌; 宝音贺西

    2016-01-01

    近地小行星与地球碰撞虽然罕见但可能会造成灾难性后果。近年来,各国加强了对近地小行星的监控、跟踪力度,并且实施了几次卓有成效的探测任务,如何防御近地小行星威胁的研究越来越多。总结了目前近地小行星的主要观测监视设施和现状,讨论了国际上对小行星威胁的评估情况,分析和评估了目前提出的防御手段的研究现状及其可行性。%Terrestrial impact by a near-Earth asteroid or comet occurs rare but may result in potentially catastrophic hazard.The researches on how to defense threat of near-Earth asteroids attract more and more attention. The paper summarizes the current situation of survey and detection of near-Earth asteroids and the major survey telescopes. And it also discusses the current state of assessing the potential impact risk and sequence in the recent researches. Finally, several proposed approaches that could prevent or mitigate the effects of potential impacting of near-Earth asteroids are analyzed and evaluated.

  19. Klenot Project - Near Earth Objects Follow-Up Program

    Science.gov (United States)

    Tichý, Miloš; Tichá, Jana; Kočer, Michal

    2016-01-01

    NEO research is a great challenge just now - for science, for exploration and for planetary defence. Therefore NEO discoveries, astrometric follow-up, orbit computations as well as physical studies are of high interest both to science community and humankind. The KLENOT Project of the Klet Observatory, South Bohemia, Czech Republic pursued the confirmation, early follow-up, long-arc follow-up and recovery of Near Earth Objects since 2002. Tens of thousands astrometric measurements helped to make inventory of NEOs as well as to understand the NEO population. It ranked among the world most prolific professional NEO follow-up programmes during its first phase from 2002 to 2008. The fundamental improvement of the 1.06-m KLENOT Telescope was started in autumn 2008. The new computer controlled paralactic mount was built to substantially increase telescope-time efficiency, the number of observations, their accuracy and limiting magnitude. The testing observations of the KLENOT Telescope Next Generation (NG) were started in October 2011. The new more efficient CCD camera FLI ProLine 230 was installed in summer 2013. The original Klet Software Package has been continually upgraded over the past two decades of operation. Along with huge hardware changes we have decided for essential changes in software and the whole KLENOT work-flow. Using the current higher computing power available, enhancing and updating our databases and astrometry program, the core of our software package, will prove highly beneficial. Moreover, the UCAC4 as the more precise astrometric star catalog was implemented. The modernized KLENOT System was put into full operation in September 2013. This step opens new possibilities for the KLENOT Project, the long-term European Contribution to Monitoring and Cataloging Near Earth Objects. KLENOT Project Goals are confirmatory observations of newly discovered fainter NEO candidates, early follow-up of newly discovered NEOs, long-arc follow-up astrometry of NEOs

  20. The Double Asteroid Redirection Test (DART) for the AIDA Mission

    Science.gov (United States)

    Stickle, Angela; Cheng, Andy F.; Michel, Patrick; Barnouin, Olivier S.; Campo Bagatin, Adriano; Miller, Paul L.; Pravec, Petr; Richardson, Derek C.; Schwartz, Stephen R.; Tsiganis, Kleomenis; Ulamec, Stephan; AIDA Impact Modeling and Simulation Working Group

    2016-10-01

    The Asteroid Impact Deflection Assessment (AIDA) mission will be the first space experiment to demonstrate asteroid impact hazard mitigation using a kinetic impactor. AIDA is a joint ESA-NASA cooperative project, consisting of the NASA Double Asteroid Redirection Test (DART) mission, which provides the kinetic impactor, and the ESA Asteroid Impact Mission (AIM) rendezvous spacecraft. DART is a Phase A study supported by NASA, and AIM is a Phase B1 study supported by ESA. The AIDA target is the near-Earth binary asteroid 65803 Didymos, which will make a close approach to Earth in October, 2022. The DART spacecraft is designed to impact the Didymos secondary at ~6 km/s and deflect its trajectory, changing the orbital period of the binary. This change can be measured by Earth-based optical and radar observations. The primary goals of AIDA are to (1) perform a full-scale demonstration of asteroid deflection by kinetic impact; (2) measure the resulting deflection; and (3) validate and improve models for momentum transfer in high-speed impacts on an asteroid. The combined DART and AIM missions will provide the first measurements of momentum transfer efficiency from a kinetic impact at full scale on an asteroid, where the impact conditions of the projectile are known, and physical properties and internal structures of the target asteroid are also characterized. In addition to a predicted 4.4 minute change in the binary orbit period, assuming unit momentum transfer efficiency, the DART kinetic impact is predicted to induce forced librations of the Didymos secondary of possibly several degrees amplitude. Models predict the impact will create a 6-17 meter diameter crater, depending on target physical properties, and it will release a volume of particulate ejecta that may be directly observable from Earth or even resolvable as a coma or an ejecta tail by ground-based telescopes. Current simulations of the DART impact provide predictions for momentum transfer, crater size, and

  1. KLENOT Project - Near Earth Objects Follow-up Program

    Science.gov (United States)

    Tichy, Milos; Ticha, Jana; Kocer, Michal; Tichy, Milos

    2015-08-01

    Near Earth Object (NEO) research is important not only as a great challenge for science but also as an important challenge for planetary defense. Therefore NEO discoveries, astrometric follow-up, orbit computations as well as physical studies are of high interest both to science community and humankind.The KLENOT Project of the Klet Observatory, South Bohemia, Czech Republic pursued the confirmation, early follow-up, long-arc follow-up and recovery of NEOs since 2002. Tens of thousands astrometric measurements helped to make inventory of NEOs as well as to understand the NEO distribution. It ranked among the world most prolific professional NEO follow-up programmes during its first phase from 2002 to 2008.The fundamental improvement of the 1.06-m KLENOT Telescope was started in autumn 2008. The new computer controlled paralactic mount was built to substantially increase telescope-time efficiency, the number of observations, their accuracy and limiting magnitude. The testing observations of the KLENOT Telescope Next Generation were started in October 2011. The new more efficient CCD camera FLI ProLine 230 was installed in summer 2013.The original Klet Software Package has been continually upgraded over the past two decades of operation.Both the system and strategy for the NEO follow-up observation used in the framework of the KLENOT Project are described here, including methods for selecting useful and important targets for NEO follow-up astrometry.The modernized KLENOT System was put into full operation in September 2013. More than 8000 of minor planet and comet astrometric positions including NEA measurements were published from September 2013 to February 2015.The 1.06-m KLENOT telescope is still the largest telescope in continental Europe used exclusively for observations of asteroids and comets. Full observing time is dedicated to the KLENOT team. Considering our results and long-time experience obtained at the Klet Observatory, we have the large potential to

  2. The Double Asteroid Redirection Test in the AIDA Mission

    Science.gov (United States)

    Cheng, Andrew; Reed, Cheryl; Rivkin, Andrew

    2016-07-01

    The Asteroid Impact & Deflection Assessment (AIDA) mission will be the first space experiment to demonstrate asteroid impact hazard mitigation by using a kinetic impactor. AIDA is a joint ESA-NASA cooperative project, consisting of the ESA Asteroid Impact Mission (AIM) rendezvous mission and the NASA Double Asteroid Redirection Test (DART) mission. The AIDA target is the near-Earth binary asteroid 65803 Didymos, which will make an unusually close approach to Earth in October, 2022. The DART spacecraft is designed to impact the Didymos secondary at 7 km/s and demonstrate the ability to modify its trajectory through momentum transfer. DART and AIM are currently Phase A studies supported by NASA and ESA respectively. The primary goals of AIDA are (1) perform a full-scale demonstration of the spacecraft kinetic impact technique for deflection of an asteroid; (2) measure the resulting asteroid deflection, by targeting the secondary member of a binary NEO and measuring the resulting changes of the binary orbit; and (3) study hyper-velocity collision effects on an asteroid, validating models for momentum transfer in asteroid impacts based on measured physical properties of the asteroid surface and sub-surface, and including long-term dynamics of impact ejecta. The primary DART objectives are to demonstrate a hyper-velocity impact on the Didymos moon and to determine the resulting deflection from ground-based observations. The DART impact on the Didymos secondary will change the orbital period of the binary which can be measured by supporting Earth-based optical and radar observations. The baseline DART mission launches in December, 2020 to impact the Didymos secondary in September,2022. There are multiple launch opportunities for DART leading to impact around the 2022 Didymos close approach to Earth. The AIM spacecraft will be launched in Dec. 2020 and arrive at Didymos in spring, 2022, several months before the DART impact. AIM will characterize the Didymos binary system

  3. The Main-belt Asteroid and NEO Tour with Imaging and Spectroscopy (MANTIS)

    Science.gov (United States)

    Rivkin, A.; Cohen, B. A.; Barnouin, O. S.; Chabot, N. L.; Ernst, C. M.; Klima, R. L.; Helbert, J.; Sternovsky, Z.

    2015-12-01

    The asteroids preserve information from the earliest times in solar system history, with compositions in the population reflecting the material in the solar nebula and experiencing a wide range of temperatures. Today they experience ongoing processes, some of which are shared with larger bodies but some of which are unique to their size regime. They are critical to humanity's future as potential threats, resource sites, and targets for human visitation. However, over twenty years since the first spacecraft encounters with asteroids, they remain poorly understood. The mission we propose here, the Main-belt Asteroid and NEO Tour with Imaging and Spectroscopy (MANTIS), explores the diversity of asteroids to understand our solar system's past history, its present processes, and future opportunities and hazards. MANTIS addresses many of NASA's highest priorities as laid out in its 2014 Science Plan and provides additional benefit to the Planetary Defense and Human Exploration communities via a low-risk, cost-effective tour of the near-Earth and inner asteroid belt. MANTIS visits the materials that witnessed solar system formation and its earliest history, addressing the NASA goal of exploring and observing the objects in the solar system to understand how they formed and evolve. MANTIS measures OH, water, and organic materials via several complementary techniques, visiting and sampling objects known to have hydrated minerals and addressing the NASA goal of improving our understanding of the origin and evolution of life on Earth. MANTIS studies the geology and geophysics of nine diverse asteroids, with compositions ranging from water-rich to metallic, representatives of both binary and non-binary asteroids, and sizes covering over two orders of magnitude, providing unique information about the chemical and physical processes shaping the asteroids, addressing the NASA goal of advancing the understanding of how the chemical and physical processes in our solar system

  4. Meteorite Source Regions as Revealed by the Near-Earth Object Population

    Science.gov (United States)

    Binzel, Richard P.; DeMeo, Francesca E.; Burt, Brian J.; Polishook, David; Burbine, Thomas H.; Bus, Schelte J.; Tokunaga, Alan; Birlan, Mirel

    2014-11-01

    Spectroscopic and taxonomic information is now available for 1000 near-Earth objects, having been obtained through both targeted surveys (e.g. [1], [2], [3]) or resulting from all-sky surveys (e.g. [4]). We determine their taxonomic types in the Bus-DeMeo system [5] [6] and subsequently examine meteorite correlations based on spectral analysis (e.g. [7],[8]). We correlate our spectral findings with the source region probabilities calculated using the methods of Bottke et al. [9]. In terms of taxonomy, very clear sources are indicated: Q-, Sq-, and S-types most strongly associated with ordinary chondrite meteorites show clear source signatures through the inner main-belt. V-types are relatively equally balanced between nu6 and 3:1 resonance sources, consistent with the orbital dispersion of the Vesta family. B- and C-types show distinct source region preferences for the outer belt and for Jupiter family comets. A Jupiter family comet source predominates for the D-type near-Earth objects, implying these "asteroidal" bodies may be extinct or dormant comets [10]. Similarly, near-Earth objects falling in the spectrally featureless "X-type" category also show a strong outer belt and Jupiter family comet source region preference. Finally the Xe-class near-Earth objects, which most closely match the spectral properties of enstatite achondrite (aubrite) meteorites seen in the Hungaria region[11], show a source region preference consistent with a Hungaria origin by entering near-Earth space through the Mars crossing and nu6 resonance pathways. This work supported by the National Science Foundation Grant 0907766 and NASA Grant NNX10AG27G.[1] Lazzarin, M. et al. (2004), Mem. S. A. It. Suppl. 5, 21. [2] Thomas, C. A. et al. (2014), Icarus 228, 217. [3] Tokunaga, A. et al. (2006) BAAS 38, 59.07. [4] Hasselmann, P. H., Carvano, J. M., Lazzaro, D. (2011) NASA PDS, EAR-A-I0035-5-SDSSTAX-V1.0. [5] Bus, S.J., Binzel, R.P. (2002). Icarus 158, 146. [6] DeMeo, F.E. et al. (2009), Icarus

  5. First Results from the Rapid-response Spectrophotometric Characterization of Near-Earth Objects using UKIRT

    Science.gov (United States)

    Mommert, M.; Trilling, D. E.; Borth, D.; Jedicke, R.; Butler, N.; Reyes-Ruiz, M.; Pichardo, B.; Petersen, E.; Axelrod, T.; Moskovitz, N.

    2016-04-01

    Using the Wide Field Camera for the United Kingdom Infrared Telescope (UKIRT), we measure the near-infrared colors of near-Earth objects (NEOs) in order to put constraints on their taxonomic classifications. The rapid-response character of our observations allows us to observe NEOs when they are close to the Earth and bright. Here we present near-infrared color measurements of 86 NEOs, most of which were observed within a few days of their discovery, allowing us to characterize NEOs with diameters of only a few meters. Using machine-learning methods, we compare our measurements to existing asteroid spectral data and provide probabilistic taxonomic classifications for our targets. Our observations allow us to distinguish between S-complex, C/X-complex, D-type, and V-type asteroids. Our results suggest that the fraction of S-complex asteroids in the whole NEO population is lower than the fraction of ordinary chondrites in the meteorite fall statistics. Future data obtained with UKIRT will be used to investigate the significance of this discrepancy.

  6. First Results from the Rapid-Response Spectrophotometric Characterization of Near-Earth Objects using UKIRT

    CERN Document Server

    Mommert, M; Borth, D; Jedicke, R; Butler, N; Reyes-Ruiz, M; Pichardo, B; Petersen, E; Axelrod, T; Moskovitz, N

    2016-01-01

    Using the Wide Field Camera for the United Kingdom Infrared Telescope, we measure the near-infrared colors of near-Earth objects (NEOs) in order to put constraints on their taxonomic classifications. The rapid-response character of our observations allows us to observe NEOs when they are close to the Earth and bright. Here we present near-infrared color measurements of 86 NEOs, most of which were observed within a few days of their discovery, allowing us to characterize NEOs with diameters of only a few meters. Using machine-learning methods, we compare our measurements to existing asteroid spectral data and provide probabilistic taxonomic classifications for our targets. Our observations allow us to distinguish between S-complex, C/X-complex, D-type, and V-type asteroids. Our results suggest that the fraction of S-complex asteroids in the whole NEO population is lower than the fraction of ordinary chondrites in the meteorite fall statistics. Future data obtained with UKIRT will be used to investigate the sig...

  7. FIRST RESULTS FROM THE RAPID-RESPONSE SPECTROPHOTOMETRIC CHARACTERIZATION OF NEAR-EARTH OBJECTS USING UKIRT

    Energy Technology Data Exchange (ETDEWEB)

    Mommert, M.; Trilling, D. E.; Petersen, E. [Department of Physics and Astronomy, Northern Arizona University, Flagstaff, AZ 86001 (United States); Borth, D. [Deutsches Forschungszentrum für Künstliche Intelligenz (DFKI), D-67663 Kaiserslautern (Germany); Jedicke, R. [Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI 96822 (United States); Butler, N. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States); Reyes-Ruiz, M. [Universidad Nacional Autónoma de México, Instituto de Astronomía, Ensenada, B.C. 22860, México (Mexico); Pichardo, B. [Instituto de Astronomía, Universidad Nacional Autónoma de México, Ciudad Universitaria, D.F. 04510, México (Mexico); Axelrod, T. [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Moskovitz, N., E-mail: michael.mommert@nau.edu [Lowell Observatory, Flagstaff, AZ 86001 (United States)

    2016-04-15

    Using the Wide Field Camera for the United Kingdom Infrared Telescope (UKIRT), we measure the near-infrared colors of near-Earth objects (NEOs) in order to put constraints on their taxonomic classifications. The rapid-response character of our observations allows us to observe NEOs when they are close to the Earth and bright. Here we present near-infrared color measurements of 86 NEOs, most of which were observed within a few days of their discovery, allowing us to characterize NEOs with diameters of only a few meters. Using machine-learning methods, we compare our measurements to existing asteroid spectral data and provide probabilistic taxonomic classifications for our targets. Our observations allow us to distinguish between S-complex, C/X-complex, D-type, and V-type asteroids. Our results suggest that the fraction of S-complex asteroids in the whole NEO population is lower than the fraction of ordinary chondrites in the meteorite fall statistics. Future data obtained with UKIRT will be used to investigate the significance of this discrepancy.

  8. Near-Earth water sources: Ethics and fairness

    Science.gov (United States)

    Schwartz, James S. J.

    2016-08-01

    There is a small finite upper bound on the amount of easily accessible water in near-Earth space, including water from C-type NEAs and permanently shadowed lunar craters. Recent estimates put this total at about 3.7 ×1012kg . Given the non-renewable nature of this resource, we should begin thinking carefully about the regulation of near-Earth water sources (NEWS). This paper discusses this issue from an ethical vantage point, and argues that for the foreseeable future, the scientific use of NEWS should be prioritized over other potential uses of NEWS.

  9. Small Solar Electric Propulsion Spacecraft Concept for Near Earth Object and Inner Solar System Missions

    Science.gov (United States)

    Lang, Jared J.; Randolph, Thomas M.; McElrath, Timothy P.; Baker, John D.; Strange, Nathan J.; Landau, Damon; Wallace, Mark S.; Snyder, J. Steve; Piacentine, Jamie S.; Malone, Shane; Bury, Kristen M.; Tracy, William H.

    2011-01-01

    Near Earth Objects (NEOs) and other primitive bodies are exciting targets for exploration. Not only do they provide clues to the early formation of the universe, but they also are potential resources for manned exploration as well as provide information about potential Earth hazards. As a step toward exploration outside Earth's sphere of influence, NASA is considering manned exploration to Near Earth Asteroids (NEAs), however hazard characterization of a target is important before embarking on such an undertaking. A small Solar Electric Propulsion (SEP) spacecraft would be ideally suited for this type of mission due to the high delta-V requirements, variety of potential targets and locations, and the solar energy available in the inner solar system.Spacecraft and mission trades have been performed to develop a robust spacecraft design that utilizes low cost, off-the-shelf components that could accommodate a suite of different scientific payloads for NEO characterization. Mission concepts such as multiple spacecraft each rendezvousing with different NEOs, single spacecraft rendezvousing with separate NEOs, NEO landers, as well as other inner solar system applications (Mars telecom orbiter) have been evaluated. Secondary launch opportunities using the Expendable Secondary Payload Adapter (ESPA) Grande launch adapter with unconstrained launch dates have also been examined.

  10. Diagnostic Comparisons of Near-Earth Object Identification using Slit Spectroscopy and Slitless Grating Methods

    Science.gov (United States)

    Ryan, E.; Ryan, W.

    2014-09-01

    Space object identification and characterization is an important component of Space Situational Awareness (SSA). Through an Air Force collaboration that has provided a visible wavelength, low-resolution spectrometer, researchers at the Magdalena Ridge Observatory 2.4-meter telescope (located in New Mexico) have been investigating the advantages and disadvantages of using slit spectroscopy versus slitless grating methods to characterize artificial Earth-orbiting objects. The objective is to develop a method that returns useful diagnostic information with a minimal investment in observational monitoring time. However, spectral measurements are a desirable component of characterization studies of natural objects in near-Earth orbit as well. Therefore, in 2012, we began to extend this instrumentation beyond its SSA applications to the study of Near-Earth asteroids (NEAs). The typical lifetimes of NEAs are up to three orders of magnitude shorter than the typical timescales associated with the main asteroid belt. Therefore, the current NEA population is a relatively recent product that has to be continually re-supplied. Spectroscopic analysis of NEAs helps characterize their taxonomic distribution and identify potential source regions which would then enhance our understanding of the origin of the current population. Although this is of interest scientifically, it can also help estimate the magnitude of the hazard threat from still undiscovered asteroids as well as provide guidance to optimize ground-based telescope search strategies. Slit-based spectroscopy is time consuming and has limitations on how faint an object can be studied. Therefore, the goal of this current project is to determine whether a lower resolution (by a factor of 10 with respect to the slit-based spectrometer), readily available slitless grating is sufficient for rough taxonomic classification in the study of fainter target-of-opportunity NEAs. The grating provides spectral information in 20nm

  11. Asteroids IV

    Science.gov (United States)

    Michel, Patrick; DeMeo, Francesca E.; Bottke, William F.

    easy and pleasant as possible for the editors, authors, and referees. They also thank Richard Binzel, the General Editor of the Space Science Series, for his strong support and advice during this process, as well as the staff at the University of Arizona Press. Finally, editor Patrick Michel would like to thank his wife Delphine, who married him on June 14, 2013, almost at the birth of the book process. He is grateful that she was willing to put up with him as he spent many of his nights and weekends working on the book. Thanks to her support, their trajectories are as bounded as a perfectly stable asteroid binary system, and this was probably the best way to experience from the start what her life would be like with a researcher! Co-editor Bottke would also like to thank his wife Veronica and his children Kristina-Marie, Laura, and Julie, who make up his own favorite asteroid family. Since Asteroids III, the size distribution of the family members has been steadily changing, and who knows how many tiny new members it will contain by Asteroids V! Co-editor DeMeo would like to thank her husband Alfredo for his support and encouragement throughout the process of creating this book. They met at the beginning of her career in research, becoming an asteroid pair and now continuing on the same orbit in life.

  12. Characterization of the Interior Density Structure of Near Earth Objects with Muons

    Science.gov (United States)

    Prettyman, T. H.; Sykes, M. V.; Miller, R. S.; Pinsky, L. S.; Empl, A.; Nolan, M. C.; Koontz, S. L.; Lawrence, D. J.; Mittlefehldt, D. W.; Reddell, B. D.

    2015-12-01

    Near Earth Objects (NEOs) are a diverse population of short-lived asteroids originating from the main belt and Jupiter family comets. Some have orbits that are easy to access from Earth, making them attractive as targets for science and exploration as well as a potential resource. Some pose a potential impact threat. NEOs have undergone extensive collisional processing, fragmenting and re-accreting to form rubble piles, which may be compositionally heterogeneous (e.g., like 2008 TC3, the precursor to Almahata Sitta). At present, little is known about their interior structure or how these objects are held together. The wide range of inferred NEO macroporosities hint at complex interiors. Information about their density structure would aid in understanding their formation and collisional histories, the risks they pose to human interactions with their surfaces, the constraints on industrial processing of NEO resources, and the selection of hazard mitigation strategies (e.g., kinetic impactor vs nuclear burst). Several methods have been proposed to characterize asteroid interiors, including radar imaging, seismic tomography, and muon imaging (muon radiography and tomography). Of these, only muon imaging has the potential to determine interior density structure, including the relative density of constituent fragments. Muons are produced by galactic cosmic ray showers within the top meter of asteroid surfaces. High-energy muons can traverse large distances through rock with little deflection. Muons transmitted through an Itokawa-sized asteroid can be imaged using a compact hodoscope placed on or near the surface. Challenges include background rejection and correction for variations in muon production with surface density. The former is being addressed by hodoscope design. Surface density variations can be determined via radar or muon limb imaging. The performance of muon imaging is evaluated for prospective NEO interior-mapping missions.

  13. ExploreNEOs: The Warm Spitzer Near Earth Object survey

    NARCIS (Netherlands)

    Mueller, M.; Trilling, D. E.; Hora, J. L.; Harris, A. W.; Benner, L. A. M.; Bhattacharya, B.; Bottke, W. F.; Chesley, S.; Delbó, M.; Emery, J. P.; Fazio, G.; Hagen, A. R.; Kistler, J. L.; Mainzer, A.; Mommert, M.; Morbidelli, A.; Penprase, B.; Smith, H. A.; Spahr, T. B.; Stansberry, J. A.; Thomas, C. A.

    2011-01-01

    We are carrying out the ExploreNEOs project in which we observe more than 600 near Earth Objects (NEOs) at 3.6 and 4.5 microns with Warm Spitzer. For each NEO we derive diameter and albedo. We present our results to date, which include studies of individual objects, results for our entire observed s

  14. ExploreNEOs: The Warm Spitzer Near Earth Object Survey

    NARCIS (Netherlands)

    Trilling, D. E.; Hora, J. L.; Mueller, M.; Thomas, C. A.; Harris, A. W.; Hagen, A. R.; Mommert, M.; Benner, L.; Bhattacharya, B.; Bottke, W. F.; Chesley, S.; Delbo, M.; Emery, J. P.; Fazio, G.; Kistler, J. L.; Mainzer, A.; Morbidelli, A.; Penprase, B.; Smith, H. A.; Spahr, T. B.; Stansberry, J. A.

    2012-01-01

    We have observed some 600 near Earth objects (NEOs) at 3.6 and 4.5 microns with the Warm Spitzer Space Telescope. We derive the albedo and diameter for each NEO to characterize global properties of the NEO population, among other goals.

  15. NEOWISE Reactivation Mission Year Two: Asteroid Diameters and Albedos

    CERN Document Server

    Nugent, C R; Bauer, J; Cutri, R M; Kramer, E A; Grav, T; Masiero, J; Sonnett, S; Wright, E L

    2016-01-01

    The Near-Earth Object Wide-Field Infrared Survey Explorer (NEOWISE) mission continues to detect, track, and characterize minor planets. We present diameters and albedos calculated from observations taken during the second year since the spacecraft was reactivated in late 2013. These include 207 near-Earth asteroids and 8,885 other asteroids. $84\\%$ of the near-Earth asteroids did not have previously measured diameters and albedos by the NEOWISE mission. Comparison of sizes and albedos calculated from NEOWISE measurements with those measured by occultations, spacecraft, and radar-derived shapes shows accuracy consistent with previous NEOWISE publications. Diameters and albedos fall within $ \\pm \\sim20\\%$ and $\\pm\\sim40\\%$, 1-sigma, respectively, of those measured by these alternate techniques. NEOWISE continues to preferentially discover near-Earth objects which are large ($>100$ m), and have low albedos.

  16. Results from the LCOGT Near-Earth Object Follow-up Network

    Science.gov (United States)

    Greenstreet, Sarah; Lister, Tim; Gomez, Edward; Christensen, Eric; Larson, Steve

    2015-11-01

    Las Cumbres Observatory Global Telescope Network (LCOGT) has deployed a homogeneous telescope network of nine 1-meter and two 2-meter telescopes to five locations in the northern and southern hemispheres, with plans to extend to twelve 1-meter telescopes at 6 locations. The versitility and design of this network allows for rapid response to target of opportunity events as well as the long-term monitoring of slowly changing astronomical phenomena. The network's global coverage and the apertures of telescopes available make LCOGT ideal for follow-up and characterization of Solar System objects (e.g. asteroids, Kuiper Belt Objects, comets, Near-Earth Objects (NEOs)) and ultimately for the discovery of new objects.LCOGT has completed the first phase of the deployment with the installation and commissioning of the nine 1-meter telescopes at McDonald Observatory (Texas), Cerro Tololo (Chile), SAAO (South Africa) and Siding Spring Observatory (Australia). This is complimented by the two 2-meter telescopes at Haleakala (Hawaii) and Siding Spring Observatory. The telescope network has been fully operational since May 2014, and observations are being executed remotely and robotically. Future expansion to sites in the Canary Islands and Tibet are planned for 2016.The LCOGT near-Earth object group is using the network to confirm newly detected NEO candidates produced by the major sky surveys such as Catalina Sky Survey (CSS), PanSTARRS (PS1) and NEOWISE, with several hundred targets being followed per year. Follow-up astrometry and photometry of radar-targeted objects and those on the Near-Earth Object Human Space Flight Accessible Targets Study (NHATS) or Asteroid Retrieval Mission (ARM) lists are improving orbits, producing light curves and rotation periods, and better characterizing these NEOs. Recent results include the first period determinations for several of the Goldstone-targeted NEOs. In addition, we are in the process of building a NEO portal that will allow

  17. Earth-approaching asteroids: Populations, origin, and compositional types

    Science.gov (United States)

    Shoemaker, E. M.; Helin, E. F.

    1978-01-01

    Origin, physical properties, and discovery history of smaller asteroids are reviewed. They appear to link the main belt objects, namely the comets and meteorites. Physical observations suggest that a wide variety of compositional types are represented among the near-earth asteroids; the apparent rarity of carbonaceous objects is stated.

  18. Dynamics and control of a solar collector system for near Earth object deflection *

    Institute of Scientific and Technical Information of China (English)

    Shen-Ping Gong; Jun-Feng Li; Yun-Feng Gao

    2011-01-01

    A solar collector system is a possible method using solar energy to deflect Earth-threatening near-Earth objects. We investigate the dynamics and control of a solar collector system including a main collector (MC) and secondary collector (SC).The MC is used to collect the sunlight to its focal point, where the SC is placed and directs the collected light to an asteroid. Both the relative position and attitude of the two collectors should be accurately controlled to achieve the desired optical path. First,the dynamical equation of the relative motion of the two collectors in the vicinity of the asteroid is modeled. Secondly, the nonlinear sliding-mode method is employed to design a control law to achieve the desired configuration of the two collectors. Finally,the deflection capability of this solar collector system is compared with those of the gravitational tractor and solar sail gravitational tractor. The results show that the solar collector is much more efficient with respect to deflection capability.

  19. The Bias-Corrected Taxonomic Distribution of Mission-Accessible Small Near-Earth Objects

    Science.gov (United States)

    Hinkle, Mary L.; Moskovitz, Nicholas; Trilling, David; Binzel, Richard P.; Thomas, Cristina; Christensen, Eric; DeMeo, Francesca; Person, Michael J.; Polishook, David; Willman, Mark

    2015-11-01

    Although they are thought to compose the majority of the Near-Earth object (NEO) population, the small (d GMOS at Gemini North & South observatories as well as the DeVeny spectrograph at Lowell Observatory's Discovery Channel Telescope. Archival data of 43 objects from the MIT-UH-IRTF Joint Campaign for NEO Spectral Reconnaissance (PI R. Binzel) were also used. Taxonomic classifications were obtained by fitting our spectra to the mean reflectance spectra of the Bus asteroid taxonomy (Bus & Binzel 2002). Small NEAs are the likely progenitors of meteorites; an improved understanding of the abundance of meteorite parent body types in the NEO population improves understanding of how the two populations are related as well as the biases Earth's atmosphere imposes upon the meteorite collection.We present classifications for these objects as well as results for the debiased distribution of taxa(as a proxy for composition) as a function of object size and compare to the observed fractions of ordinary chondritemeteorites and asteroids with d > 1 km. Amongst the smallest NEOs we find an unexpected distribution of taxonomic types that differs from both large NEOs and meteorites.We acknowledge funding support from NASA NEOO grant number NNX14AN82G.

  20. NEOWISE REACTIVATION MISSION YEAR ONE: PRELIMINARY ASTEROID DIAMETERS AND ALBEDOS

    Energy Technology Data Exchange (ETDEWEB)

    Nugent, C. R.; Cutri, R. M. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Mainzer, A.; Masiero, J.; Bauer, J.; Kramer, E.; Sonnett, S.; Stevenson, R. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Grav, T. [Planetary Science Institute, Tucson, AZ (United States); Wright, E. L., E-mail: cnugent@ipac.caltech.edu [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States)

    2015-12-01

    We present preliminary diameters and albedos for 7956 asteroids detected in the first year of the NEOWISE Reactivation mission. Of those, 201 are near-Earth asteroids and 7755 are Main Belt or Mars-crossing asteroids. 17% of these objects have not been previously characterized using the Near-Earth Object Wide-field Infrared Survey Explorer, or “NEOWISE” thermal measurements. Diameters are determined to an accuracy of ∼20% or better. If good-quality H magnitudes are available, albedos can be determined to within ∼40% or better.

  1. On the existence of near-Earth-object meteoroid complexes producing meteorites

    Science.gov (United States)

    Trigo-Rodriguez, J.; Madiedo, J.; Williams, I.

    2014-07-01

    It is generally thought that meteorites are formed as a result of collisions within the main belt of asteroids [1]. They are delivered onto Earth-crossing orbits because of the effects of orbital resonances, primarily with Jupiter. About 15 meteorites are known where their passage through the atmosphere was observed and recorded, allowing the parameters of the pre-encounter orbit to be derived [2]. The cosmic-ray-exposure ages (CREAs) are suggesting that most meteorites have been exposed to cosmic rays for tens of millions of years (Myrs) [3], re-enforcing the belief that the process of modifying the orbit from being near-circular in the main belt to highly elliptical as an Earth-crossing orbit was a gradual process like the effects of resonance. However, there is growing evidence that some meteorite could originate directly from the near-Earth-object (NEO) population. A good example of this is the recent discovery of rare primitive groups in the Antarctic, an example being Elephant Moraine (EET) 96026: a C4/5 carbonaceous chondrite with a measured cosmic ray exposure age of only 0.28 Ma [4]. Here, we focus on recent dynamic links that have been established between meteorite-dropping bolides and NEOs that support the idea of short-life meteoroid streams that can generate meteoroids on Earth. The fact that such streams can exist allows rocky material from potentially-hazardous asteroids (PHA) to be sampled and investigated in the laboratory. The existence of meteoroid streams capable of producing meteorites has been proposed following the determination of accurate meteoroid orbits of fireballs obtained by the Canadian Meteorite Observation and Recovery Project (MORP) [5]. Some asteroids in the Earth's vicinity are undergoing both dynamical and collisional evolution on very short timescales [6]. Many of these objects are crumbly bodies that originated from the collisions between main-belt asteroids during their life-time. An obvious method of forming these complexes

  2. An ISU study of asteroid mining

    Science.gov (United States)

    Burke, J. D.

    1991-01-01

    During the 1990 summer session of the International Space University, 59 graduate students from 16 countries carried out a design project on using the resources of near-earth asteroids. The results of the project, whose full report is now available from ISU, are summarized. The student team included people in these fields: architecture, business and management, engineering, life sciences, physical sciences, policy and law, resources and manufacturing, and satellite applications. They designed a project for transporting equipment and personnel to a near-earth asteroid, setting up a mining base there, and hauling products back for use in cislunar space. In addition, they outlined the needed precursor steps, beginning with expansion of present ground-based programs for finding and characterizing near-earth asteroids and continuing with automated flight missions to candidate bodies. (To limit the summer project's scope the actual design of these flight-mission precursors was excluded.) The main conclusions were that asteroid mining may provide an important complement to the future use of lunar resources, with the potential to provide large amounts of water and carbonaceous materials for use off earth. However, the recovery of such materials from presently known asteroids did not show an economic gain under the study assumptions; therefore, asteroid mining cannot yet be considered a prospective business.

  3. Unveiling clues from Spacecraft Missions to Comets and Asteroids through Impact Experiments

    Science.gov (United States)

    Lederer, Susan M.; Jensen, Elizabeth; Fane, Michael; Smith, Douglas; Holmes, Jacob; Keller, Lindsay P.; Lindsay, Sean S.; Wooden, Diane H.; Whizin, Akbar; Cintala, Mark J.; Zolensky, Michael

    2016-10-01

    The Deep Impact Spacecraft mission was the first to boldly face the challenge of impacting the surface of a comet, 9P/Tempel 1, to investigate surface and subsurface 'pristine' materials. The Stardust mission to Comet 81P/Wild 2 brought back an exciting surprise: shocked minerals which were likely altered during the comet's lifetime. Signatures of shock in meteorites also suggest that the violent past of the solar system has left our small bodies with signatures of impacts and collisions. These results have led to the question: How have impacts affected the evolutionary path taken by comets and asteroids, and what signatures can be observed?A future planetary mission to a near-Earth asteroid is proposing to take the next steps toward understanding small bodies through impacts. The mission would combine an ESA led AIM (Asteroid Impact Mission) with a JHU/APL led DART (Double Asteroid Redirect Mission) spacecraft to rendezvous with binary near-Earth asteroid 65803 Didymus (1996 G2). DART would impact the smaller asteroid, 'Didymoon' while AIM would characterize the impact and the larger Didymus asteroid.With these missions in mind, a suite of experiments have been conducted at the Experimental Impact Laboratory (EIL) at NASA Johnson Space Center to investigate the effects that collisions may have on comets and asteroids. With the new capability of the vertical gun to cool targets in the chamber through the use of a cold jacket fed by liquid nitrogen, the effects of target temperature have been the focus of recent studies. Mg-rich forsterite and enstatite (orthopyroxene), diopside (monoclinic pyroxene) and magnesite (Mg-rich carbonate) were impacted. Target temperatures ranged from 25°C to -100°C, monitored by connecting thermocouples to the target container. Impacted targets were analyzed with a Fourier Transform Infrared Spectrometer (FTIR) and Transmission Electron Microscope (TEM). Here we present the evidence for impact-induced shock in the minerals through

  4. Asteroids Lightcurves Analysis: 2015 October-December

    Science.gov (United States)

    Carbognani, Albino; Buzzi, Luca

    2016-04-01

    Eight asteroids, main-belt (MBA) and near-Earth (NEA), were observed in 2015 Oct-Dec: 6853 Silvanomassaglia, (112985) 2002 RS28, (155110) 2005 TB, (163899) 2003 SD220, (253106) 2002 UR3, (337866) 2001 WL15, 2015 XC, and 2015 WG9.

  5. The orbital distribution of Near-Earth Objects inside Earth's orbit

    Science.gov (United States)

    Greenstreet, Sarah; Ngo, Henry; Gladman, Brett

    2012-01-01

    Canada's Near-Earth Object Surveillance Satellite (NEOSSat), set to launch in early 2012, will search for and track Near-Earth Objects (NEOs), tuning its search to best detect objects with a Morbidelli, A., Jedicke, R., Petit, J.M., Levison, H.F., Michel, P., Metcalfe, T.S. [2002]. Icarus 156, 399-433) provides. We present here the NEOSSat-1.0 NEO orbital distribution model with larger statistics that permit finer resolution and less uncertainty, especially in the a < 1.0 AU region. We find that Amors = 30.1 ± 0.8%, Apollos = 63.3 ± 0.4%, Atens = 5.0 ± 0.3%, Atiras (0.718 < Q < 0.983 AU) = 1.38 ± 0.04%, and Vatiras (0.307 < Q < 0.718 AU) = 0.22 ± 0.03% of the steady-state NEO population. Vatiras are a previously undiscussed NEO population clearly defined in our integrations, whose orbits lie completely interior to that of Venus. Our integrations also uncovered the unexpected production of retrograde orbits from main-belt asteroid sources; this retrograde NEA population makes up ≃0.1% of the steady-state NEO population. The relative NEO impact rate onto Mercury, Venus, and Earth, as well as the normalized distribution of impact speeds, was calculated from the NEOSSat-1.0 orbital model under the assumption of a steady-state. The new model predicts a slightly higher Mercury impact flux.

  6. How to Communicate Near Earth Objects with the Public - Klet Observatory Experience

    Science.gov (United States)

    Ticha, Jana; Tichy, Milos; Kocer, Michal

    2015-08-01

    Near-Earth Object (NEO) research is counted among the most popular parts of communicating astronomy with the public. Increasing research results in the field of Near-Earth Objects as well as impact hazard investigations cause growing interest among general public and media. Furthermore NEO related issues have outstanding educational value. So thus communicating NEO detection, NEO characterization, possible impact effects, space missions to NEOs, ways of mitigation and impact warnings with the public and media belong to the most important tasks of scientists and research institutions.Our institution represents an unique liaison of the small professional research institution devoted especially to NEO studies (the Klet Observatory, Czech Republic) and the educational and public outreach branch (the Observatory and Planetarium Ceske Budejovice, Czech Republic). This all has been giving us an excellent opportunity for bringing NEO information to wider audience. We have been obtaining a wide experience in communicating NEOs with the public more than twenty years.There is a wide spectrum of public outreach tools aimed to NEO research and hazard. As the most useful ones we consider two special on-line magazines (e-zins) devoted to asteroids (www.planetky.cz) and comets (www.komety.cz) in Czech language, educational multimedia presentations for schools at different levels in planetarium, summer excursions for wide public just at the Klet Observatory on the top of the Klet mountain, public lectures, meetings and exhibitions. It seems to be very contributing and favoured by public to have opportunities for more or less informal meetings just with NEO researchers from time to time. Very important part of NEO public outreach consists of continuous contact with journalists and media including press releases, interviews, news, periodical programs. An increasing role of social media is taken into account through Facebook and Twitter profiles.The essential goal of all mentioned NEO

  7. Mitigation of Hazardous Comets and Asteroids

    Science.gov (United States)

    Belton, Michael J. S.; Morgan, Thomas H.; Samarasinha, Nalin H.; Yeomans, Donald K.

    2011-03-01

    Preface; 1. Recent progress in interpreting the nature of the near-Earth object population W. Bottke, A. Morbidelli and R. Jedicke; 2. Earth impactors: orbital characteristics and warning times S. R. Chesley and T. B. Spahr; 3. The role of radar in predicting and preventing asteroid and comet collisions with Earth S. J. Ostro and J. D. Giorgini; 4. Interior structures for asteroids and cometary nuclei E. Asphaug; 5. What we know and don't know about surfaces of potentially hazardous small bodies C. R. Chapman; 6. About deflecting asteroids and comets K. A. Holsapple; 7. Scientific requirements for understanding the near-Earth asteroid population A. W. Harris; 8. Physical properties of comets and asteroids inferred from fireball observations M. D. Martino and A. Cellino; 9. Mitigation technologies and their requirements C. Gritzner and R. Kahle; 10. Peering inside near-Earth objects with radio tomography W. Kofman and A. Safaeinili; 11. Seismological imvestigation of asteroid and comet interiors J. D. Walker and W. F. Huebner; 12. Lander and penetrator science for near-Earth object mitigation studies A. J. Ball, P. Lognonne, K. Seiferlin, M. Patzold and T. Spohn; 13. Optimal interpretation and deflection of Earth-approaching asteroids using low-thrust electric propulsion B. A. Conway; 14. Close proximity operations at small bodies: orbiting, hovering, and hopping D. J. Scheeres; 15. Mission operations in low gravity regolith and dust D. Sears, M. Franzen, S. Moore, S. Nichols, M. Kareev and P. Benoit; 16. Impacts and the public: communicating the nature of the impact hazard D. Morrison, C. R. Chapman, D. Steel and R. P. Binzel; 17. Towards a program to remove the threat of hazardous NEOs M. J. S. Belton.

  8. Assessment of DSN Communication Coverage for Space Missions to Potentially Hazardous Asteroids

    Science.gov (United States)

    Kegege, Obadiah; Bittner, David; Gati, Frank; Bhasin, Kul

    2012-01-01

    A communication coverage gap exists for Deep Space Network (DSN) antennas. This communication coverage gap is on the southern hemisphere, centered at approximate latitude of -47deg and longitude of -45deg. The area of this communication gap varies depending on the altitude from the Earth s surface. There are no current planetary space missions that fall within the DSN communication gap because planetary bodies in the Solar system lie near the ecliptic plane. However, some asteroids orbits are not confined to the ecliptic plane. In recent years, Potentially Hazardous Asteroids (PHAs) have passed within 100,000 km of the Earth. NASA s future space exploration goals include a manned mission to asteroids. It is important to ensure reliable and redundant communication coverage/capabilities for manned space missions to dangerous asteroids that make a sequence of close Earth encounters. In this paper, we will describe simulations performed to determine whether near-Earth objects (NEO) that have been classified as PHAs fall within the DSN communication coverage gap. In the study, we reviewed literature for a number of PHAs, generated binary ephemeris for selected PHAs using JPL s HORIZONS tool, and created their trajectories using Satellite Took Kit (STK). The results show that some of the PHAs fall within DSN communication coverage gap. This paper presents the simulation results and our analyses

  9. Are Near Earth Objects the Key to Optimization Theory?

    CERN Document Server

    Formato, Richard A

    2009-01-01

    This note suggests that near earth objects and Central Force Optimization have something in common, that NEO theory may hold the key to solving some vexing problems in deterministic optimization: local trapping and proof of convergence. CFO analogizes Newton's laws to locate the global maxima of a function. The NEO-CFO nexus is the striking similarity between CFO's Davg and an NEO's Delta-V curves. Both exhibit oscillatory plateau-like regions connected by jumps, suggesting that CFO's metaphorical "gravity" indeed behaves like real gravity, thereby connecting NEOs and CFO and being the basis for speculating that NEO theory may address difficult issues in optimization.

  10. Space Mobile Network: A Near Earth Communication and Navigation Architecture

    Science.gov (United States)

    Israel, Dave J.; Heckler, Greg; Menrad, Robert J.

    2016-01-01

    This paper describes a Space Mobile Network architecture, the result of a recently completed NASA study exploring architectural concepts to produce a vision for the future Near Earth communications and navigation systems. The Space Mobile Network (SMN) incorporates technologies, such as Disruption Tolerant Networking (DTN) and optical communications, and new operations concepts, such as User Initiated Services, to provide user services analogous to a terrestrial smartphone user. The paper will describe the SMN Architecture, envisioned future operations concepts, opportunities for industry and international collaboration and interoperability, and technology development areas and goals.

  11. The search for Near Earth Objects - why dark skies are critically important

    Science.gov (United States)

    Wainscoat, Richard

    2015-08-01

    Impact of Earth by asteroids is perhaps the only natural disaster that can be prevented. If an asteroid that will impact Earth can be identified sufficiently early, it is possible to modify its orbit to eliminate the impact. As a consequence, a major effort is presently underway to identify Near Earth Objects (NEOs) that may present a threat to Earth. The impact of a 20-meter diameter object near Chelyabinsk, Russia, provided a spectacular reminder of the threat that these objects present. Although no deaths were caused, injuries and a large amount of property damage were caused.The search for NEOs is mostly funded by NASA. The principal search telescopes are the Pan-STARRS telescopes, located on Haleakala, Maui, Hawaii, and the Catalina Sky Survey, located near Tucson, Arizona. Both of these locations are seriously threatened by light pollution. A new survey, ATLAS, will commence shortly, with one telescope located on Haleakala, Maui, and the other telescope located on Mauna Loa, Hawaii (which is less threatened).Artificial light (i.e., light pollution) at these observing sites raises the sky background, and makes faint objects harder or impossible to see.Searches for Near Earth Objects typically use very broad passbands in order to obtain the maximum amount of light. These passbands typically stretch from 400 to 820 nm. As such, they are very vulnerable to the changes in lighting that are occurring across the globe, with widespread introduction of blue-rich white lighting. It is critically important in all of these locations to limit the amount of blue light that is so readily scattered by the atmosphere.A network of followup telescopes, spread across the planet, play a crucial role in the discovery of NEOs. After a new NEO is identified by the survey telescopes such as Pan-STARRS and Catalina, additional observations must be secured to establish its orbit, and in order to determine whether it poses a threat to Earth. The majority of these followup telescopes are

  12. Unified Propulsion System to Explore Near-Earth Asteroids by a 50 kg Spacecraft

    OpenAIRE

    Koizumi, Hiroyuki; Inagaki, Tadashi; Kasagi, Yusuke; Naoi, Taro; Hayashi, Tomoyuki; Funase, Ryu; Komurasaki, Kimiya

    2014-01-01

    In this study, the micropropulsion system I-COUPS (Ion Thruster and COld-gas Thruster Unified Propulsion System) is proposed for 50-kg-class spacecraft to explore the deep space. The I-COUPS is a unified propulsion system of ion thrusters and cold-gas thrusters by sharing the same xenon gas system. It provides the spacecraft with high ΔV maneuver, high thrust, short time maneuver, and reaction control by eight thrusters. The total wet mass of the propulsion system is expected to 9.5 kg with 2...

  13. Near-Earth Asteroid Offers Rare Chance for a Close Look

    Institute of Scientific and Technical Information of China (English)

    Leslie; Fink; 李孜

    2008-01-01

    科学家们发现一颗直径达2000英尺的小行星正朝地球飞速驶来!不过不用担心,它将在334000英里外与地球擦肩而过,并不会对我们造成任何伤害;相反,它将给科学家们提供一次研究小行星的绝好机会。如果你是位狂热的天文爱好者,想必也不会放过这一千载难逢的机会。赶快拿出你的宝贝们摆好架势吧!

  14. Finding Near-Earth Asteroid (NEA) Destinations for Human Exploration: Implications for Astrobiology

    Science.gov (United States)

    Landis, Rob; Abell, Paul; Barbee, Brent; Johnson, Lindley

    2012-01-01

    The current number of known potential NEA targets for HSF is limited to those objects whose orbital characteristics are similar to that of the Earth. This is due to the projected capabilities of the exploration systems currently under consideration and development at NASA. However, NEAs with such orbital characteristics often have viewing geometries that place them at low solar elongations and thus are difficult to detect from the vicinity of Earth. While ongoing ground-based surveys and data archives maintained by the NEO Program Observation Program Office and the Minor Planet Center (MPC) have provided a solid basis upon which to build, a more complete catalog of the NEO population is required to inform a robust and sustainable HSF exploration program. Since all the present NEO observing assets are currently confined to the vicinity of the Earth, additional effort must be made to provide capabilities for detection of additional HSF targets via assets beyond Earth orbit. A space-based NEO survey telescope located beyond the vicinity of the Earth, has considerable implications for planetary science and astrobiology. Such a telescope will provide foundational knowledge of our Solar System small body population and detect targets of interest for both the HSF and scientific communities. Data from this asset will yield basic characterization data on the NEOs observed (i.e., albedo, size determination, potential for volatiles and organics, etc.) and help down select targets for future HSF missions. Ideally, the most attractive targets from both HSF and astrobiology perspectives are those NEAs that may contain organic and volatile materials, and which could be effectively sampled at a variety of locations and depths. Presented here is an overview of four space-based survey concepts; any one of which after just a few years of operation will discover many highly accessible NEO targets suitable for robotic and human exploration. Such a space-based survey mission will reveal incredible returns for several disciplines including: exploration, in situ resource utilization, planetary defense, and science. Of particular, interest to the scientific

  15. Near-Earth bursty bulk flows and AE index

    Institute of Scientific and Technical Information of China (English)

    ZHANG LingQian; SHI JianKui; LIU ZhenXing; W BAUMJOHANN; MA ZhiWei; M. W. DUNLOP; C. CARR; H. REME

    2008-01-01

    With the 4-s resolution data of the magnetometer and the ion plasma analyzer on TC-1 from June to November of each year during the period of 2004-2006, we statistically analyzed the occurrence rate of both convective and field-aligned bursty flows (FABFs). A near-Earth bursty bulk flow (NEBBF) occurred during both the quiet time and substorm process. In general, the magnetic field and the plasma density began oscillating with the appearance of the NEBBF associated with a distinct increase of the AE index. The increase of AE index during the NEBBF was more than 100 nT in both quiet time and substorm process. The statistical analysis indicated that the occurrence rates of the FABFs were nearly the same in the dif-ferent stages of the AE index, but the occurrence rate of the NEBBFs was much higher in the growth stage of the AE index, indicating that the NEBBFs were di-rectly related to the growth and expansion phases of the substorm. The observa-tions suggested that the quite large number of BBFs from the mid magnetotail could enter into the near-Earth tail and play important role in triggering the sub-storm onset.

  16. ExploreNEOs: A Search for Near-Earth Objects of Cometary Origin

    Science.gov (United States)

    Mommert, Michael; Harris, A. W.; Trilling, D. E.; Mueller, M.; Hora, J. L.; Delbo, M.; Bottke, W. F.; Emery, J. P.; Fazio, G.; Hagen, A. R.; Morbidelli, A.; Smith, H. A.; Thomas, C. A.

    2012-10-01

    The short dynamical lifetime of near-Earth objects (NEOs) compared to the age of the Solar System implies the existence of sources of replenishment in order to maintain the observed population of NEOs. Main belt asteroids and Jupiter family comets (JFCs), which can end up in typical NEO orbits via planetary perturbations and non-gravitational forces, are the most important sources of replenishment of NEOs. JFCs that become NEOs suffer accelerated loss of their near-surface volatiles, evolving into inactive "dormant" or "extinct" comets that are observationally indistinguishable from low albedo asteroids. Dynamically, however, they retain "comet-like" orbital characteristics. Knowledge of the fraction of extinct comets in the NEO population is important for assessing the amount of cometary material that has been transported to Earth. Furthermore, identifying inactive comet candidates facilitates detailed investigations of the final phase of comet evolution. We present an independent analysis of the fraction of former cometary objects in the NEO population. Due to the large number of NEOs we use a statistical approach to identify dormant or extinct comets based on dynamical and physical properties. We utilize (1) the Tisserand parameter with respect to Jupiter, (2) the minimum orbit intersection distance with respect to Jupiter and (3) albedo measurements. Our albedos are determined from thermal-IR observations made by the Warm Spitzer Space Telescope Exploration Science project "ExploreNEOs", using thermal modeling. The main goal of this work is to estimate the fraction of dormant or extinct comets in the NEO population. We will further provide a list of former comet candidate objects and assess their accessibility with spacecraft via the delta-V parameter. We enhance our investigation by adding data from the literature to our sample and compare our results to earlier published works based on independent analyses. MM acknowledges support by the DFG SPP 1385.

  17. How Many Ultra-Low Delta-v Near Earth Objects Remain Undiscovered? Implications for missions.

    Science.gov (United States)

    Elvis, Martin; Ranjan, Sukrit; Galache, Jose Luis; Murphy, Max

    2015-08-01

    The past decade has witnessed considerable growth of interest in missions to Near-Earth Objects (NEOs). NEOs are considered prime targets for manned and robotic missions, for both scientific objectives as well as in-situ resource utilization including harvesting of water for propellant and life support and mining of high-value elements for sale on Earth. Appropriate targets are crucial to such missions. Hence, ultra-low delta-v mission targets are strongly favored. Some mission architectures rely on the discovery of more ultra-low delta-v NEOs. In fact the approved and executed NEO missions have all targeted asteroids with ultra-low LEO to asteroid rendezvous delta-v orbits using a modified Shoemaker-Helin (S-H) formalism that empirically removes biases found comparing S-H with the results from NHATS. The median delta-v of the known NEOs is 7.3 km/s, the median delta-v predicted by our NEO model is 9.8 km/s, suggesting that undiscovered objects are biased to higher delta-v. The survey of delta-v 300 m. However, there are tens of thousands of objects with delta-v <10.3 km/s to be discovered in the D = 50 - 300 m size class (H = 20.4 - 24.3). Our work suggests that there are 100 yet-undiscovered NEOs with delta-v < 5:8 km/s, and 1000 undiscovered NEOs with v < 6.3 km/s. We conclude that, even with complete NEO surveys, the selection of good (i.e. ultra-low delta-v) mission targets is limited given current propulsion technology. Visiting the full range of NEO sub-types will likely require improved propulsion systems.

  18. A Fast Ellipsoid Model for Asteroids Inverted From Lightcurves

    CERN Document Server

    Lu, Xiaoping; You, Zhong

    2012-01-01

    The research about asteroids attracts more and more attention recently, especially focusing on their physical structures, such as the spin axis, the rotation period and the shape. The long distance between Earth observers and asteroids makes it impossible to get the shape and other parameters of asteroids directly with the exception of the NEAs (Near Earth Asteroids) and others passed by some spacecrafts. Generally photometric measurement is still the main way to obtain the research data for asteroids now, i.e. the lightcurves recording the brightness and positions of asteroids. Supposing that the shape of the asteroid is a triaxial ellipsoid with a stable spinning status, a new method is present in this article to reconstruct the shape models of asteroids from the lightcurves, with the other physical parameters together. By applying a special curvature function, the method calculates the brightness integration on a unit sphere and Lebedev Quadrature is employed for the discretization. At last the method sear...

  19. The IMPACTON Project: Pole and Shape of Eight Near-Earth Asteroids†

    Science.gov (United States)

    Silva, José Sergio; Lazzaro, Daniela; Rodrigues, Teresinha; Carvano, Jorge Márcio; Roig, Fernando; Souza, Roberto; Aff001

    2016-01-01

    The formation and evolution of Solar System small bodies, in particular those in near-Earth orbits, is a complex problem which solution strongly depends on a better knowledge of their physical properties. To contribute to the international efforts in this direction the IMPACTON project (www.on.br/IMPACTON) set up a dedicated facility denominated Observatório Astronômico do Sertão de Itaparica (OASI). Using the 1-m telescope several dozens of NEAs were observed between March 2012 and October 2014. Here we will present the results obtained for 8 objects. Relative magnitudes were used to obtain lightcurves and derive rotational periods. Applying the inversion method developed by Kaasalainen and Torppa (2001) and Kaasalainen et al. (2001), along with lightcurves from literature, allowed to refine the rotational period of these asteroids as well as to derive their pole direction and shape. The obtained results confirm a lack of poles toward the ecliptic and with a majority of retrograde rotators. A more representative sample, however, is needed in order to drive robust conclusions.

  20. The near-Earth objects and their potential threat to our planet

    Science.gov (United States)

    Perna, D.; Barucci, M. A.; Fulchignoni, M.

    2013-09-01

    The near-Earth object (NEO) population includes both asteroids (NEAs) and comet nuclei (NECs) whose orbits have perihelion distances q 140 m). These are big enough to cause, in the case of impact with Earth, destructive effects on a regional scale. Smaller objects can still produce major damage on a local scale, while the largest NEOs could endanger the survival of living species. Therefore, several national and international observational efforts have been started (i) to detect undiscovered NEOs and especially PHAs, (ii) to determine and continuously monitor their orbital properties and hence their impact probability, and (iii) to investigate their physical nature. Further ongoing activities concern the analysis of possible techniques to mitigate the risk of a NEO impact, when an object is confirmed to be on an Earth colliding trajectory. Depending on the timeframe available before the collision, as well as on the object’s physical properties, various methods to deflect a NEO have been proposed and are currently under study from groups of experts on behalf of international organizations and space agencies. This paper will review our current understanding of the NEO population, the scientific aspects and the ongoing space- and ground-based activities to foresee close encounters and to mitigate the effects of possible impacts.

  1. Modeling the Performance of the LSST in Surveying the Near-Earth Object Population

    CERN Document Server

    Grav, Tommy; Spahr, Tim

    2016-01-01

    We have performed a detailed survey simulation of the LSST performance with regards to near-Earth objects (NEOs) using the project's current baseline cadence. The survey shows that if the project is able to reliably generate linked sets of positions and times (a so-called "tracklet") using two detections of a given object per night and can link these tracklets into a track with a minimum of 3 tracklets covering more than a ~12 day length-of-arc, they would be able to discover 62% of the potentially hazardous asteroids (PHAs) larger than 140 m in its projected 10 year survey lifetime. This completeness would be reduced to 58% if the project is unable to implement a pipeline using the two detection cadence and has to adopt the four detection cadence more commonly used by existing NEO surveys. When including the estimated performance from the current operating surveys, assuming these would continue running until the start of LSST and perhaps beyond, the completeness fraction for PHAs larger than 140m would be 73...

  2. NEO-LISP: Deflecting near-Earth objects using high average power, repetitively pulsed lasers

    Science.gov (United States)

    Phipps, C. R.; Michaelis, M. M.

    Several kinds of Near-Earth objects exist for which one would like to cause modest orbit perturbations, but which are inaccessible to normal means of interception because of their number, distance or the lack of early warning. For these objects, LISP (Laser Impulse Space Propulsion) is an appropriate technique for rapidly applying the required mechanical impulse from a ground-based station. In order of increasing laser energy required, examples are: (1) repositioning specially prepared geosynchronous satellites for an enhanced lifetime; (2) causing selected items of space junk to re-enter and burn up in the atmosphere on a computed trajectory; and (3) safely deflecting Earth-directed comet nuclei and earth-crossing asteroids (ECA's) a few tens of meters in size (the most hazardous size). They will discuss each of these problems in turn and show that each application is best matched by its own matrix of LISP laser pulse width, pulse repetition rate, wavelength and average power. The latter ranges from 100W to 3GW for the cases considered. They will also discuss means of achieving the active beam phase error correction during passage through the atmosphere and very large exit pupil in the optical system which are required in each of these cases.

  3. Charged dust phenomena in the near-Earth space environment

    Science.gov (United States)

    Scales, W. A.; Mahmoudian, A.

    2016-10-01

    Dusty (or complex) plasmas in the Earth’s middle and upper atmosphere ultimately result in exotic phenomena that are currently forefront research issues in the space science community. This paper presents some of the basic criteria and fundamental physical processes associated with the creation, evolution and dynamics of dusty plasmas in the near-Earth space environment. Recent remote sensing techniques to probe naturally created dusty plasma regions are also discussed. These include ground-based experiments employing high-power radio wave interaction. Some characteristics of the dusty plasmas that are actively produced by space-borne aerosol release experiments are discussed. Basic models that may be used to investigate the characteristics of such dusty plasma regions are presented.

  4. Near Earth Objects - a threat and an opportunity

    Science.gov (United States)

    Tate, Jonathan R.

    2003-05-01

    In the past decade the hazard posed to the Earth by Near Earth Objects (NEOs) has generated considerable scientific and public interest. A number of major films, television programmes and media reports have brought the issue to public attention. From an educational perspective an investigation into NEOs and the effects of impacts on the Earth forms a topical and dynamic basis for study in a huge range of subjects, not just scientific. There are clear routes to chemistry, physics, mathematics and biology, but history, psychology, geography, palaeontology and geology are just a selection of other subjects involved. A number of projects have been established, mainly in the USA, to determine the extent of the hazard, and to develop ways of countering it, but the present situation is far from satisfactory. Current detection and follow-up programmes are underfunded and lack international coordination.

  5. OMNI: A Description of Near-Earth Solar Wind Environment

    Science.gov (United States)

    Papitashvili, Natasha; Bilitza, Dieter; King, Joseph

    OMNI is an hourly resolution multi-source data set of near-Earth solar wind's magnetic field and plasma parameters spanning the period from November 1963 (IMP 1 launch) to today, and it is being updated regularly with new data. OMNI is widely used in the heliospheric community as is documented by the large number of acknowledgements in scientific papers. OMNI provides the IMF (magnitude and vector), flow velocity (magnitude and vector), flow pressure, proton density, alpha particle to proton density ratio, and several additional parameters including sunspot and geomagnetic indices and energetic proton fluxes from IMP and GOES. Spacecraft data used for compiling the OMNI solar wind reference include IMP-8, ACE, Wind, ISEE-3, and Geotail. The data from ISEE-3, Wind, and ACE were time-shifted because they are about an hour upstream of the Earth's magnetosphere. Extensive quality control and cross- comparisons of overlapping data sets were made in creating OMNI. This presentation will describe the OMNI data set and highlight its wide use in the space science community. We will also present some of the many capabilities of the OMNIweb interface (http://omniweb.gsfc.nasa.gov/ow.html) that provides access to the entire OMNI data set. OMNIWeb allows users to generate plots vs. time, to create scatter plots of any two OMNI parameters, to filter with user-specified parameter range criteria, to list and download OMNI parameters, to generate distributions of OMNI parameter values, and to browse and retrieve a static (but periodically updated) daily-resolution IMF polarity plot covering the entire OMNI time span. The Omni data set represents a thorough description of various characteristics of near-Earth solar wind magnetic field and plasma, which could be used as a basis for that space environment's standard.

  6. Asteroid exploration and utilization: The Hawking explorer

    Science.gov (United States)

    Carlson, Alan; Date, Medha; Duarte, Manny; Erian, Neil; Gafka, George; Kappler, Peter; Patano, Scott; Perez, Martin; Ponce, Edgar; Radovich, Brian

    1991-01-01

    The Earth is nearing depletion of its natural resources at a time when human beings are rapidly expanding the frontiers of space. The resources which may exist on asteroids could have enormous potential for aiding and enhancing human space exploration as well as life on Earth. With the possibly limitless opportunities that exist, it is clear that asteroids are the next step for human existence in space. This report comprises the efforts of NEW WORLDS, Inc. to develop a comprehensive design for an asteroid exploration/sample return mission. This mission is a precursor to proof-of-concept missions that will investigate the validity of mining and materials processing on an asteroid. Project STONER (Systematic Transfer of Near Earth Resources) is based on two utilization scenarios: (1) moving an asteroid to an advantageous location for use by Earth; and (2) mining an asteroids and transporting raw materials back to Earth. The asteroid explorer/sample return mission is designed in the context of both scenarios and is the first phase of a long range plane for humans to utilize asteroid resources. The report concentrates specifically on the selection of the most promising asteroids for exploration and the development of an exploration scenario. Future utilization as well as subsystem requirements of an asteroid sample return probe are also addressed.

  7. Ground-Based Near-Earth Object Studies in the post-Russian (Chelyabinsk) Meteor Airburst World

    Science.gov (United States)

    Ryan, E.; Ryan, W. H.

    2013-09-01

    Public awareness of the danger of potentially hazardous asteroids has been heightened by the airburst of a meteor over Chelyabinsk, Russia, on February 15, 2013, which caused millions of dollars in damage from a shock wave that impacted structures and injured ~1500 people. Later that same day, a larger asteroid, 2012 DA14, made a close approach to the Earth, but harmlessly skimmed past. Further, other very close-approaching Near-Earth objects (NEOs) have recently posed threats to man-made space assets by passing through or very near the geosynchronous satellite zone. These events have lead to increased awareness and concern, and have subsequently served as a catalyst for deeper exploration of what is being done to mitigate such hazards, and whether more effort needs to be placed in this area of study. An NEO is designated as "potentially hazardous" when its orbit comes to within 0.05 AU of the Earth's orbit. Ground-based physical characterization studies of Near-Earth Objects (NEOs) that are cataloged as potentially hazardous objects (PHOs) are very beneficial to any mitigation plan that might be devised if the risk of impact is high. After a well-defined orbit has been determined for a PHO, other physical parameters such as size, rotation rate, and composition are important. For the smallest PHOs being discovered, observational efforts must commence at or near the time of discovery to ensure favorable parameters for data collection. Otherwise, subsequent optimal apparitions for observing an asteroid or comet may be decades away. Researchers at the Magdalena Ridge Observatory (MRO) 2.4-meter telescope facility are well positioned to acquire real-time physical information on PHOs since their ongoing NEO follow-up and characterization program collects data monthly throughout the year on the smallest, close-approaching NEOs being discovered. Over the past 5 years that this program has been in operation, spin rates for over 50 Near-Earth asteroids have been obtained

  8. The Ginger-shaped Asteroid 4179 Toutatis: New Observations from a Successful Flyby of Chang'e-2

    CERN Document Server

    Huang, Jiangchuan; Ye, Peijian; Wang, Xiaolei; Yan, Jun; Meng, Linzhi; Wang, Su; Li, Chunlai; Li, Yuan; Qiao, Dong; Zhao, Wei; Zhao, Yuhui; Zhang, Tingxin; Liu, Peng; Jiang, Yun; Rao, Wei; Li, Sheng; Huang, Changning; Ip, Wing-Huen; Hu, Shoucun; Zhu, Menghua; Yu, Liangliang; Zou, Yongliao; Tang, Xianglong; Li, Jianyang; Zhao, Haibin; Huang, Hao; Jiang, Xiaojun; Bai, Jinming

    2013-01-01

    On 13 December 2012, Chang'e-2 conducted a successful flyby of the near-Earth asteroid 4179 Toutatis at a closest distance of 770 $\\pm$ 120 meters from the asteroid's surface. The highest-resolution image, with a resolution of better than 3 meters, reveals new discoveries on the asteroid, e.g., a giant basin at the big end, a sharply perpendicular silhouette near the neck region, and direct evidence of boulders and regolith, which suggests that Toutatis may bear a rubble-pile structure. Toutatis' maximum physical length and width are (4.75 $\\times$ 1.95 km) $\\pm$10$\\%$, respectively, and the direction of the +$z$ axis is estimated to be (250$\\pm$5$^\\circ$, 63$\\pm$5$^\\circ$) with respect to the J2000 ecliptic coordinate system. The bifurcated configuration is indicative of a contact binary origin for Toutatis, which is composed of two lobes (head and body). Chang'e-2 observations have significantly improved our understanding of the characteristics, formation, and evolution of asteroids in general.

  9. Additional spectra of asteroid 1996 FG3, backup target of the ESA MarcoPolo-R mission

    CERN Document Server

    de Leon, J; Ali-Lagoa, V; Licandro, J; Pinilla-Alonso, N; Campins, H

    2013-01-01

    Near-Earth binary asteroid (175706) 1996 FG3 is the current backup target of the ESA MarcoPolo-R mission, selected for the study phase of ESA M3 missions. It is a primitive (C-type) asteroid that shows significant variation in its visible and near-infrared spectra. Here we present new spectra of 1996 FG3 and we compare our new data with other published spectra, analysing the variation in the spectral slope. The asteroid will not be observable again over the next three years at least. We obtained the spectra using DOLORES and NICS instruments at the Telescopio Nazionale Galileo (TNG), a 3.6m telescope located at El Roque de los Muchachos Observatory in La Palma, Spain. To compare with other published spectra of the asteroid, we computed the spectral slope S', and studied any plausible correlation of this quantity with the phase angle (alpha). In the case of visible spectra, we find a variation in spectral slope of Delta S' = 0.15 +- 0.10 %/10^3 A/degree for 3 < alpha < 18 degrees, in good agreement with ...

  10. The ginger-shaped asteroid 4179 Toutatis: new observations from a successful flyby of Chang'e-2.

    Science.gov (United States)

    Huang, Jiangchuan; Ji, Jianghui; Ye, Peijian; Wang, Xiaolei; Yan, Jun; Meng, Linzhi; Wang, Su; Li, Chunlai; Li, Yuan; Qiao, Dong; Zhao, Wei; Zhao, Yuhui; Zhang, Tingxin; Liu, Peng; Jiang, Yun; Rao, Wei; Li, Sheng; Huang, Changning; Ip, Wing-Huen; Hu, Shoucun; Zhu, Menghua; Yu, Liangliang; Zou, Yongliao; Tang, Xianglong; Li, Jianyang; Zhao, Haibin; Huang, Hao; Jiang, Xiaojun; Bai, Jinming

    2013-12-12

    On 13 December 2012, Chang'e-2 conducted a successful flyby of the near-Earth asteroid 4179 Toutatis at a closest distance of 770 ± 120 meters from the asteroid's surface. The highest-resolution image, with a resolution of better than 3 meters, reveals new discoveries on the asteroid, e.g., a giant basin at the big end, a sharply perpendicular silhouette near the neck region, and direct evidence of boulders and regolith, which suggests that Toutatis may bear a rubble-pile structure. Toutatis' maximum physical length and width are (4.75 × 1.95 km) ±10%, respectively, and the direction of the +z axis is estimated to be (250 ± 5°, 63 ± 5°) with respect to the J2000 ecliptic coordinate system. The bifurcated configuration is indicative of a contact binary origin for Toutatis, which is composed of two lobes (head and body). Chang'e-2 observations have significantly improved our understanding of the characteristics, formation, and evolution of asteroids in general.

  11. The Ginger-shaped Asteroid 4179 Toutatis: New Observations from a Successful Flyby of Chang'e-2

    Science.gov (United States)

    Huang, Jiangchuan; Ji, Jianghui; Ye, Peijian; Wang, Xiaolei; Yan, Jun; Meng, Linzhi; Wang, Su; Li, Chunlai; Li, Yuan; Qiao, Dong; Zhao, Wei; Zhao, Yuhui; Zhang, Tingxin; Liu, Peng; Jiang, Yun; Rao, Wei; Li, Sheng; Huang, Changning; Ip, Wing-Huen; Hu, Shoucun; Zhu, Menghua; Yu, Liangliang; Zou, Yongliao; Tang, Xianglong; Li, Jianyang; Zhao, Haibin; Huang, Hao; Jiang, Xiaojun; Bai, Jinming

    2013-12-01

    On 13 December 2012, Chang'e-2 conducted a successful flyby of the near-Earth asteroid 4179 Toutatis at a closest distance of 770 +/- 120 meters from the asteroid's surface. The highest-resolution image, with a resolution of better than 3 meters, reveals new discoveries on the asteroid, e.g., a giant basin at the big end, a sharply perpendicular silhouette near the neck region, and direct evidence of boulders and regolith, which suggests that Toutatis may bear a rubble-pile structure. Toutatis' maximum physical length and width are (4.75 × 1.95 km) +/-10%, respectively, and the direction of the +z axis is estimated to be (250 +/- 5°, 63 +/- 5°) with respect to the J2000 ecliptic coordinate system. The bifurcated configuration is indicative of a contact binary origin for Toutatis, which is composed of two lobes (head and body). Chang'e-2 observations have significantly improved our understanding of the characteristics, formation, and evolution of asteroids in general.

  12. Near-Earth Objects: Targets for Future Human Exploration, Solar System Science, Resource Utilization, and Planetary Defense

    Science.gov (United States)

    Abell, Paul A.

    2011-01-01

    U.S. President Obama stated on April 15, 2010 that the next goal for human spaceflight will be to send human beings to a near-Earth asteroid by 2025. Given this direction from the White House, NASA has been involved in studying various strategies for near-Earth object (NEO) exploration in order to follow U.S. Space Exploration Policy. This mission would be the first human expedition to an interplanetary body beyond the Earth-Moon system and would prove useful for testing technologies required for human missions to Mars and other Solar System destinations. Missions to NEOs would undoubtedly provide a great deal of technical and engineering data on spacecraft operations for future human space exploration while conducting in-depth scientific investigations of these primitive objects. In addition, the resulting scientific investigations would refine designs for future extraterrestrial resource extraction and utilization, and assist in the development of hazard mitigation techniques for planetary defense. This presentation will discuss some of the physical characteristics of NEOs and review some of the current plans for NEO research and exploration from both a human and robotic mission perspective.

  13. Preservation of Near-Earth Space for Future Generations

    Science.gov (United States)

    Simpson, John A.

    2007-05-01

    List of contributors; Preface; Part I. Introduction: 1. Introduction J. A. Simpson; Part II. Defining the Problem: 2. The Earth satellite population: official growth and constituents Nicholas L. Johnson; 3. The current and future environment: an overall assessment Donald J. Kessler; 4. The current and future space debris environment as assessed in Europe Dietrich Rex; 5. Human survivability issues in the low Earth orbit space debris environment Bernard Bloom; 6. Protecting the space environment for astronomy Joel R. Primack; 7. Effects of space debris on commercial spacecraft - the RADARSAT example H. Robert Warren and M. J. Yelle; 8. Potential effects of the space debris environment on military space systems Albert E. Reinhardt; Part III. Mitigation of and Adaptation to the Space Environment: Techniques and Practices: 9. Precluding post-launch fragmentation of delta stages Irvin J. Webster and T. Y. Kawamura; 10. US international and interagency cooperation in orbital debris Daniel V. Jacobs; 11. ESA concepts for space debris mitigation and risk reduction Heiner Klinkrad; 12. Space debris: how France handles mitigation and adaptation Jean-Louis Marcé; 13. Facing seriously the issue of protection of the outer space environment Qi Yong Liang; 14. Space debris - mitigation and adaptation U. R. Rao; 15. Near Earth space contamination and counteractions Vladimir F. Utkin and S. V. Chekalin; 16. The current and future space debris environment as assessed in Japan Susumu Toda; 17. Orbital debris minimization and mitigation techniques Joseph P. Loftus Jr, Philip D. Anz-Meador and Robert Reynolds; Part IV. Economic Issues: 18. In pursuit of a sustainable space environment: economic issues in regulating space debris Molly K. Macauley; 19. The economics of space operations: insurance aspects Christopher T. W. Kunstadter; Part V. Legal Issues: 20. Environmental treatymaking: lessons learned for controlling pollution of outer space Winfried Lang; 21. Regulation of orbital

  14. Project RAMA: Reconstructing Asteroids Into Mechanical Automata

    Science.gov (United States)

    Dunn, Jason; Fagin, Max; Snyder, Michael; Joyce, Eric

    2017-01-01

    Many interesting ideas have been conceived for building space-based infrastructure in cislunar space. From O'Neill's space colonies, to solar power satellite farms, and even prospecting retrieved near earth asteroids. In all the scenarios, one thing remained fixed - the need for space resources at the outpost. To satisfy this need, O'Neill suggested an electromagnetic railgun to deliver resources from the lunar surface, while NASA's Asteroid Redirect Mission called for a solar electric tug to deliver asteroid materials from interplanetary space. At Made In Space, we propose an entirely new concept. One which is scalable, cost effective, and ensures that the abundant material wealth of the inner solar system becomes readily available to humankind in a nearly automated fashion. We propose the RAMA architecture, which turns asteroids into self-contained spacecraft capable of moving themselves back to cislunar space. The RAMA architecture is just as capable of transporting conventional-sized asteroids on the 10-meter length scale as transporting asteroids 100 meters or larger, making it the most versatile asteroid retrieval architecture in terms of retrieved-mass capability. This report describes the results of the Phase I study funded by the NASA NIAC program for Made In Space to establish the concept feasibility of using space manufacturing to convert asteroids into autonomous, mechanical spacecraft. Project RAMA, Reconstituting Asteroids into Mechanical Automata, is designed to leverage the future advances of additive manufacturing (AM), in-situ resource utilization (ISRU) and in-situ manufacturing (ISM) to realize enormous efficiencies in repeated asteroid redirect missions. A team of engineers at Made In Space performed the study work with consultation from the asteroid mining industry, academia, and NASA. Previous studies for asteroid retrieval have been constrained to studying only asteroids that are both large enough to be discovered, and small enough to be

  15. Stream and sporadic meteoroids associated with Near Earth Objects

    CERN Document Server

    Jopek, Tadeusz J

    2014-01-01

    NEOs come close to the Earth's orbit so that any dust ejected from them, might be seen as a meteor shower. Orbits evolve rapidly, so that a similarity of orbits at one given time is not suffcient to prove a relationship, orbital evolution over a long time interval also has to be similar. Sporadic meteoroids can not be associated with a single parent body, they can only be classified as cometary or asteroidal. However, by considering one parameter criteria, many sporadics are not classified properly therefore two parameter approach was proposed.

  16. The Catalina Sky Survey for Near-Earth Objects

    Science.gov (United States)

    Christensen, Eric J.; Carson Fuls, David; Gibbs, Alex; Grauer, Al; Johnson, Jess Andrew; Kowalski, Richard; Larson, Stephen M.; Leonard, Gregory; Matheny, Rose; Seaman, Robert L.; Shelly, Frank

    2016-10-01

    The Catalina Sky Survey (CSS) operates three telescopes on Mt. Lemmon, Arizona, in support of NASA's effort to detect and catalog near-Earth objects (NEOs). CSS is undergoing a period of significant enhancement, including the installation of two large-format cameras built around monolithic 10k x 10k detectors, which replace our reliable but aging 4k x 4k cameras at the survey telescopes. These new cameras increase the field of view (FoV) of our 0.7-meter Schmidt telescope by a factor of 2.4 (from 8.1 deg2 to 19.4 deg2), and the FoV of our 1.5-meter telescope by a factor of 4 (from 1.2 deg2 to 5.0 deg2), enabling significantly more sky to be surveyed every night. Other recent improvements include the conversion to a more modern telescope control system, the addition of an image subtraction-based enhancement to our moving object detection software, and the deployment of a custom adaptive queue scheduler.We will present a brief overview of survey operations, discussing the balance between human-driven decisions and automation. Results from the new camera commissioning will also be presented, and we will introduce a new project to reprocess the CSS archival holdings with an enhanced pipeline, and publicly serve the data via PDS.CSS is supported by NASA under grant #NNX15AF79G.

  17. Review of the near-earth space radiation dosimetry

    Science.gov (United States)

    Guo, Jianming; Chen, Xiaoqian; Li, Shiyou

    2016-07-01

    The near-earth space radiation environment has a great effect to the spacecraft and maybe do harm to the astronaut's health. Thus, how to measure the radiation has become a serious challenge. In order to provide sufficient protection both for astronauts and for instruments on-board, dose equivalent and linear energy transfer should be measured instead of merely measuring total radiation dose. This paper reviews the methods of radiation measurement and presents a brief introduction of dosimetry instruments. The method can be divided into two different kinds, i.e., positive dosimetry and passive dosimetry. The former usually includes electronic devices which can be used for data storage and can offer simultaneous monitoring on space radiation. The passive dosimetry has a much simple structure, and need extra operation after on-orbit missions for measuring. To get more reliable data of radiation dosimetry, various instruments and methods had been applied in the spacecrafts and the manned spacecrafts in particular. The outlook of the development in the space radiation dosimetry measurement is also presented.

  18. Neutron measurements in near-Earth orbit with COMPTEL

    Science.gov (United States)

    Morris, D. J.; Aarts, H.; Bennett, K.; Lockwood, J. A.; Mcconnell, M. L.; Ryan, J. M.; Schoenfelder, V.; Steinle, H.; Peng, X.

    1995-01-01

    The fast neutron flux in near-Earth orbit has been measured with the COMPTEL instrument on the Compton Gamma Ray Observatory (CGRO). For this measurement one of COMPTEL's seven liquid scintillator modules was used as an uncollimated neutron detector with threshold of 12.8 MeV. The measurements cover a range of 4.8 to 15.5 GV in vertical cutoff rigidity and 3 deg to 177 deg in spacecraft geocenter zenith angle. One of the measurements occurred near the minimum of the deepest Forbush decrease ever observed by ground-level neutron monitors. After correction for solar modulation, the total flux is well fitted by separable functions in rigidity and zenith angle. With the spacecraft pointed near the nadir the flux is consistent with balloon measurements of the atmospheric neutron albedo. The flux varies by about a factor of 4 between the extremes of rigidity and a factor of 2 between the extremes of zenith angle. The effect of the spacecraft mass in shielding the detector from the atmospheric neutron albedo is much more important than its role as a source of additional secondary neutrons. The neutron spectral hardness varies little with rigidity or zenith angle and lies in the range spanned by earlier atmospheric neutron albedo measurements.

  19. Neutron measurements in near-Earth orbit with COMPTEL

    Energy Technology Data Exchange (ETDEWEB)

    Morris, D.J.; Aarts, H.; Bennett, K.; Lockwood, J.A.; Mcconnell, M.L.; Ryan, J.M.; Schoenfelder, V.; Steinle, H.; Peng, X. [Max-Planck-Institut fuer extraterrestrische Physik, Garching (Germany)]|[SRON-Utrecht, Utrecht, Netherlands]|[European Space Research and Technology Centre, Noordwijk, Netherlands]|[University of New Hampshire, Durham, NH, US

    1995-07-01

    The fast neutron flux in near-Earth orbit has been measured with the COMPTEL instrument on the Compton Gamma Ray Observatory (CGRO). For this measurement one of COMPTEL`s seven liquid scintillator modules was used as an uncollimated neutron detector with threshold of 12.8 MeV. The measurements cover a range of 4.8 to 15.5 GV in vertical cutoff rigidity and 3 deg to 177 deg in spacecraft geocenter zenith angle. One of the measurements occurred near the minimum of the deepest Forbush decrease ever observed by ground-level neutron monitors. After correction for solar modulation, the total flux is well fitted by separable functions in rigidity and zenith angle. With the spacecraft pointed near the nadir the flux is consistent with balloon measurements of the atmospheric neutron albedo. The flux varies by about a factor of 4 between the extremes of rigidity and a factor of 2 between the extremes of zenith angle. The effect of the spacecraft mass in shielding the detector from the atmospheric neutron albedo is much more important than its role as a source of additional secondary neutrons. The neutron spectral hardness varies little with rigidity or zenith angle and lies in the range spanned by earlier atmospheric neutron albedo measurements.

  20. NEOKepler: Discovering Near-Earth Objects Using the Kepler Spacecraft

    CERN Document Server

    Stevenson, Kevin B; Jedicke, Robert; Bottke, William; Denneau, Larry

    2013-01-01

    We propose a new Kepler mission, called NEOKepler, that would survey near Earth's orbit to identify potentially hazardous objects (PHOs). To understand its surveying power, Kepler's large field of view produces an 'etendue' (A*Omega) that is 4.5 times larger than the best survey telescope currently in operation. In this paper, we investigate the feasibility of NEOKepler using a double "fence post" survey pattern that efficiently detects PHOs. In a simulated 12-month survey, we estimate that NEOKepler would detect ~150 new NEOs with absolute magnitudes of less than 21.5, ~50 of which would be new PHOs. This would increase the annual PHO discovery rate by at least 50% and improve upon our goal of discovering 90% of PHOs by the end of 2020. Due to its heliocentric orbit, Kepler would also be sensitive to objects inside Earth's orbit, discovering more objects in its first year than are currently known to exist. Understanding this undersampled sub-population of NEOs will reveal new insights into the actual PHO dis...

  1. Capturing small asteroids into a Sun-Earth Lagrangian point

    Science.gov (United States)

    Lladó, Neus; Ren, Yuan; Masdemont, Josep J.; Gómez, Gerard

    2014-02-01

    In this paper we address the feasibility of capturing small Near-Earth Asteroids (NEAs) into the vicinity of the Sun-Earth L2 libration point using a continuous-thrust propulsion system assumed to be attached to the asteroid. The vicinity of this libration point is a gateway to the Earth-Moon neighborhood and using it for capture, or for transit, small NEAs could be interesting for mining or science purposes.

  2. Near Earth space plasma monitoring under COST 296

    Directory of Open Access Journals (Sweden)

    Jürgen Bremer

    2009-06-01

    Full Text Available

    This review paper presents the main achievements of the near Earth space plasma monitoring under COST 296

    Action. The outputs of the COST 296 community making data, historical and real-time, standardized and available to the ionospheric community for their research, applications and modeling purposes are presented. The contribution of COST 296 with the added value of the validated data made possible a trusted ionospheric monitoring for research and modeling purposes, and it served for testing and improving the algorithms producing real-time

    data and providing data users measurement uncertainties. These value added data also served for calibration and

    validation of space-borne sensors. New techniques and parameters have been developed for monitoring the near Earth space plasma, as time dependent 2D maps of vertical total electron content (vTEC, other key ionospheric parameters and activity indices for distinguishing disturbed ionospheric conditions, as well as a technique for improving the discrepancies of different mapping services. The dissemination of the above products has been developed by COST 296 participants throughout the websites making them available on-line for real-time applications.


  3. NEOLegacy: The ultimate Spitzer survey of Near Earth Objects

    Science.gov (United States)

    Trilling, David; Mommert, Michael; Hora, Joseph; Chesley, Steve; Emery, Joshua; Fazio, Giovanni; Harris, Alan; Mueller, Michael; Smith, Howard

    2016-08-01

    Near Earth Objects (NEOs) are bodies whose orbits bring them close to the Earth's orbit. NEOs are valuable tracers of the evolution of our Solar System, and are also key components of current and future space exploration. Finally, the study of NEOs is relevant for civil defense through understanding the impact threat. We propose here an efficient and comprehensive survey to measure the diameters, albedos, and lightcurves of 1154 NEOs. We include only targets that are too faint to be detected by NEOWISE. This catalog will complete a database of diameters and albedos for nearly 3000 NEOs -- more than 20% of all known objects. Our primary goal, in line with the planetary science priorities for Spitzer Cycle 13, is to create a large and uniform catalog of NEO properties. From this catalog we will calculate an independent estimate of the NEO size distribution, addressing a current controversy, and measure the compositional distribution of NEOs as a function of size. We will increase by up to a factor of five the number of NEO lightcurves with relatively well known periods and amplitudes. The legacy value of this project is most evident in the fact that there will not ever in the foreseeable future be another opportunity to measure thousands of NEO diameters and carry out the type of science described above. Our online database will be the single most valuable resource of NEO diameters and albedos for years to come. Only Spitzer is sensitive and efficient enough to create such an important catalog of this scale. Our team has unmatched experience observing NEOs with Spitzer.

  4. Visible Wavelength Reflectance Spectra and Taxonomies of Near-Earth Objects from Apache Point Observatory

    Science.gov (United States)

    Hammergren, Mark; Brucker, Melissa J.; Nault, Kristie A.; Gyuk, Geza; Solontoi, Michael R.

    2015-11-01

    Near-Earth Objects (NEOs) are interesting to scientists and the general public for diverse reasons: their impacts pose a threat to life and property; they present important albeit biased records of the formation and evolution of the Solar System; and their materials may provide in situ resources for future space exploration and habitation.In January 2015 we began a program of NEO astrometric follow-up and physical characterization using a 17% share of time on the Astrophysical Research Consortium (ARC) 3.5-meter telescope at Apache Point Observatory (APO). Our 500 hours of annual observing time are split into frequent, short astrometric runs (see poster by K. A. Nault et. al), and half-night runs devoted to physical characterization (see poster by M. J. Brucker et. al for preliminary rotational lightcurve results). NEO surface compositions are investigated with 0.36-1.0 μm reflectance spectroscopy using the Dual Imaging Spectrograph (DIS) instrument. As of August 25, 2015, including testing runs during fourth quarter 2014, we have obtained reflectance spectra of 68 unique NEOs, ranging in diameter from approximately 5m to 8km.In addition to investigating the compositions of individual NEOs to inform impact hazard and space resource evaluations, we may examine the distribution of taxonomic types and potential trends with other physical and orbital properties. For example, the Yarkovsky effect, which is dependent on asteroid shape, mass, rotation, and thermal characteristics, is believed to dominate other dynamical effects in driving the delivery of small NEOs from the main asteroid belt. Studies of the taxonomic distribution of a large sample of NEOs of a wide range of sizes will test this hypothesis.We present a preliminary analysis of the reflectance spectra obtained in our survey to date, including taxonomic classifications and potential trends with size.Acknowledgements: Based on observations obtained with the Apache Point Observatory 3.5-meter telescope, which

  5. Radar Images And Shape Model Of A Triple Asteroid (136617) 1994CC

    Science.gov (United States)

    Brozovic, Marina; Benner, L. A. M.; Nolan, M. C.; Howell, E. S.; Magri, C.; Giorgini, J. D.; Taylor, P. A.; Margot, J. L.; Busch, M. W.; Shepard, M. K.; Scheeres, D. J.; Carter, L. M.

    2010-10-01

    We report radar observations and shape modeling of asteroid (136617) 1994CC, which is only the second triple system known in the near-Earth population, after (153591) 2001 SN263. This object was observed at Goldstone (8560 MHz, 3.5 cm) and Arecibo (2380 MHz, 12.6 cm) from June 12 to June 21, 2009. The radar images and subsequent shape modeling reveal that the primary is 600 m in diameter with a shape that closely resembles that of 1999 KW4 Alpha. The secondary is 130 m in diameter and appears to be in a synchronous orbit with a period of 30 hours. The tertiary satellite is 90 m in diameter and has an orbital period of 9 days. Its semimajor axis of 20 primary radii is the largest discovered so far among near-Earth multiple systems. Among the 37 NEA binary or ternary systems currently known, 80% have been observed by radar and 2/3 were discovered by radar. Since January 1999, 17% of radar-detected NEAs with diameters greater than 200 m have been found to be multiple systems.

  6. The Rafita asteroid family

    Science.gov (United States)

    Aljbaae, S.; Carruba, V.; Masiero, J. R.; Domingos, R. C.; Huaman, M.

    2017-01-01

    The Rafita asteroid family is an S-type group located in the middle main belt, on the right side of the 3J:-1A mean-motion resonance. The proximity of this resonance to the family left side in semi-major axis caused many former family members to be lost. As a consequence, the family shape in the (a, 1/D) domain is quite asymmetrical, with a preponderance of objects on the right side of the distribution. The Rafita family is also characterized by a leptokurtic distribution in inclination, which allows the use of methods of family age estimation recently introduced for other leptokurtic families such as Astrid, Hansa, Gallia, and Barcelona. In this work we propose a new method based on the behavior of an asymmetry coefficient function of the distribution in the (a, 1/D) plane to date incomplete asteroid families such as Rafita. By monitoring the time behavior of this coefficient for asteroids simulating the initial conditions at the time of the family formation, we were able to estimate that the Rafita family should have an age of 490 ± 200 Myr, in good agreement with results from independent methods such as Monte Carlo simulations of Yarkovsky and Yorp dynamical induced evolution and the time behaviour of the kurtosis of the sin (i) distribution. Asteroids from the Rafita family can reach orbits similar to 8% of the currently known near Earth objects. ≃1% of the simulated objects are present in NEO-space during the final 10 Myr of the simulation, and thus would be comparable to objects in the present-day NEO population.

  7. Spitzer observations of two mission-accessible, tiny asteroids

    NARCIS (Netherlands)

    Mommert, M.; Hora, J.; Farnocchia, D.; Chesley, S.; Vokrouhlicky, D.; Trilling, D.; Mueller, M.; Harris, A.; Smith, H.; Fazio, G.

    2014-01-01

    Small asteroids are most likely collisional fragments of larger objects and make up a large fraction of the near-Earth-object (NEO) population. Despite their abundance, little is known about the physical properties of these objects, which is mainly due to their faintness, which also impedes their

  8. Near Earth Network (NEN) CubeSat Communications

    Science.gov (United States)

    Schaire, Scott

    2017-01-01

    The NASA Near Earth Network (NEN) consists of globally distributed tracking stations, including NASA, commercial, and partner ground stations, that are strategically located to maximize the coverage provided to a variety of orbital and suborbital missions, including those in LEO (Low Earth Orbit), GEO (Geosynchronous Earth Orbit), HEO (Highly Elliptical Orbit), lunar and L1-L2 orbits. The NEN's future mission set includes and will continue to include CubeSat missions. The first NEN-supported CubeSat mission will be the Cubesat Proximity Operations Demonstration (CPOD) launching into LEO in 2017. The majority of the CubeSat missions destined to fly on EM-1, launching in late 2018, many in a lunar orbit, will communicate with ground-based stations via X-band and will utilize the NASA Jet Propulsion Laboratory (JPL)-developed IRIS (Satellite Communication for Air Traffic Management) radio. The NEN recognizes the important role CubeSats are beginning to play in carrying out NASAs mission and is therefore investigating the modifications needed to provide IRIS radio compatibility. With modification, the NEN could potentially expand support to the EM-1 (Exploration Mission-1) lunar CubeSats. The NEN could begin providing significant coverage to lunar CubeSat missions utilizing three to four of the NEN's mid-latitude sites. This coverage would supplement coverage provided by the JPL Deep Space Network (DSN). The NEN, with smaller apertures than DSN, provides the benefit of a larger beamwidth that could be beneficial in the event of uncertain ephemeris data. In order to realize these benefits the NEN would need to upgrade stations targeted based on coverage ability and current configuration ease of upgrade, to ensure compatibility with the IRIS radio. In addition, the NEN is working with CubeSat radio developers to ensure NEN compatibility with alternative CubeSat radios for Lunar and L1-L2 CubeSats. The NEN has provided NEN compatibility requirements to several radio

  9. Asteroid Redirect

    OpenAIRE

    De Aquino, Fran

    2017-01-01

    Asteroids are a great threat to mankind. Here we will show that it is possible to redirect them from their trajectories by means of a strong gravitational repulsion, produced by the gravitational interaction between the asteroid and a Gravitational Spacecraft positioned close to the asteroid.

  10. Capture of Asteroids and Transport of Asteroid Materials to Earth

    Science.gov (United States)

    Chiu, Hong-Yee; no Team

    2014-01-01

    Recently there has been much discussion on the capture of asteroids or mining the asteroids. While the technology might be years away, in this paper we will discuss an energy efficient method to transport either a small asteroid or materials gathered from asteroids to the Earth. In particular, I will concentrate on a large and nearby asteroid, 8 Flora in the Flora Family. Generally, asteroids are located between 2 to 3 AU (astronomical unit) from the Earth, and in transporting materials from asteroids to the Earth, an energy equivalent of the gravitational potential energy difference between the Earth and the asteroids to the Sun. This amount of potential energy is a sizable fraction of the orbital kinetic energy of the Earth around the Sun. This amount of energy is considerable. In this paper I propose to use the planet Mars as a medium to remove much of the gravitational energy difference. In the case of the asteroid 8 Flora, it is only necessary to decelerate the asteroid mate- rials by a small decrement, of the order of 3 km/sec. This decrement could even be achieved (pending on the availability of technology) by mechanical devices such as catapults on 8 Flora. It is also proposed to separate a pair of contact asteroid binaries by using impulse propulsion, and to propel one component of the separated asteroids to pass by Mars to be decelerated to reach the Earth orbit and captured by the Earth or the Moon. The plausibility of this ambitious project will be discussed. The author is NASA-GSFC Astrophysicist, Retired.

  11. Hayabusa2 mission target asteroid (162173) 1999 JU_3: Searching for the object's spin-axis orientation

    NARCIS (Netherlands)

    Müller, T.; Durech, J.; Mueller, M.; Kiss, C.; Vilenius, E.; Ishiguro, M.

    2014-01-01

    The JAXA Hayabusa2 mission was approved in 2011 with launch planned for late 2014. Arriving at the asteroid (162173) 1999 JU_3 in 2018, it will survey it, land, and obtain surface material, then depart in late 2019, and return to the Earth in December 2020. We observed the near-Earth asteroid 1999 J

  12. Hayabusa2 mission target asteroid (162173) 1999 JU_3: Searching for the object's spin-axis orientation

    NARCIS (Netherlands)

    Müller, T.; Durech, J.; Mueller, M.; Kiss, C.; Vilenius, E.; Ishiguro, M.

    2014-01-01

    The JAXA Hayabusa2 mission was approved in 2011 with launch planned for late 2014. Arriving at the asteroid (162173) 1999 JU_3 in 2018, it will survey it, land, and obtain surface material, then depart in late 2019, and return to the Earth in December 2020. We observed the near-Earth asteroid 1999

  13. Automatic detection of asteroids and meteoroids. A Wide Field Survey

    Science.gov (United States)

    Vereš, P.; Tóth, J.; Jedicke, R.; Tonry, J.; Denneau, L.; Wainscoat, R.; Kornoš, L.; Šilha, J.

    2014-07-01

    We propose a low-cost robotic optical survey aimed at 1-300 m Near Earth Objects (NEO) based on four state-of-the-art telescopes having extremely wide field of view. The small Near-Earth Asteroids (NEA) represent a potential risk but also easily accessible space resources for future robotic or human space in-situ exploration, or commercial activities. The survey system will be optimized for the detection of fast moving-trailed-asteroids, space debris and will provide real-time alert notifications. The expected cost of the system including 1-year development and 2-year operation is 1,000,000 EUR. The successful demonstration of the system will promote cost-effectiveicient ADAM-WFS (Automatic Detection of Asteroids and Meteoroids -- A Wide Field Survey) systems to be built around the world.

  14. Automatic Detection of Asteroids and Meteoroids - A Wide Field Survey

    CERN Document Server

    Vereš, P; Jedicke, R; Tonry, J; Denneau, L; Wainscoat, R; Kornoš, L; Šilha, J

    2014-01-01

    We propose a low-cost robotic optical survey aimed at $1-300$ m Near Earth Objects (NEO) based on four state-of-the-art telescopes having extremely wide field of view. The small Near-Earth Asteroids (NEA) represent a potential risk but also easily accessible space resources for future robotic or human space in-situ exploration, or commercial activities. The survey system will be optimized for the detection of fast moving - trailed - asteroids, space debris and will provide real-time alert notifications. The expected cost of the system including 1-year development and 2-year operation is 1,000,000 EUR. The successful demonstration of the system will promote cost-efficient ADAM-WFS (Automatic Detection of Asteroids and Meteoroids - A Wide Field Survey) systems to be built around the world.

  15. Post-Chelyabinsk Risk Assessment for Near Earth Objects (NEOs)

    Science.gov (United States)

    Boslough, M.; Harris, A. W.

    2014-12-01

    The widely-accepted NEO risk assessments published in the 1990s concluded that the largest asteroids (> 1 km) dominated the hazard. Even though large NEOs represent only a tiny fraction of the population because of a power-law size distribution, the potential for global catastrophe means that the contribution from these low-probability, high-consequence events is large. This conclusion led to the Spaceguard survey, which has now catalogued about 90% of these objects, none of which is on a collision course. The survey has reduced the assessed risk from this size range by more than an order of magnitude because completion is highest for the largest and most dangerous. The relative risk from objects tens of meters in diameter is therefore increasing.The absolute assessed risk from airbursts caused by objects of this size is also higher for two reasons. First, they may be more frequent than previously thought because of an underestimated population. Second, they are significantly more damaging than assumed in the original assessment because (in most cases) they more efficiently couple energy to the surface than nuclear explosions. Last year's half-megaton airburst over Chelyabinsk, Russia, appears to challenge the notion that such events are extremely rare—especially when also considering the 1908 Tunguska event along with decades of infrasound bolide data showing higher-than-expected numbers of large airbursts.We will present a new analysis of the risk based on updated estimates for the population of undiscovered NEOs, taking into account the enhanced damage potential of collisional airbursts. Merging the survey population estimates with the bolide frequency estimates suggests a population of tens-of-meters sized bodies that may be a factor of three or so greater than estimated from surveys alone. Uncertainty in the population of airburst-class NEOs remains quite large, and can only be unambiguously reduced by expanded surveys focused on objects in the tens

  16. Geotechnical Tests on Asteroid Simulant Orgueil

    Science.gov (United States)

    Garcia, Alexander D'marco

    2017-01-01

    through the surface of an asteroid. Most of the known asteroids are believed to be left over material during the formation of the solar system that never accreted to form planets. Asteroids can be found in several groups such as Trojan Asteroids, Near Earth Asteroids (NEAs) and the main asteroid belt. The Trojan Asteroids orbit the 4th and 5th Lagrange points of major planets in the Solar System while the NEA's have orbits that are close to and sometimes intersect with Earths orbit and the Main Asteroid Belt which is found between the orbit of Mars and Jupiter. Gravitational perturbations can alter the orbit of asteroids in the Main Asteroid Belt causing them to move closer to earth causing them to become in the NEA class.

  17. Laboratory experiments on the impact disruption of iron meteorites at temperature of near-Earth space

    Science.gov (United States)

    Katsura, Takekuni; Nakamura, Akiko M.; Takabe, Ayana; Okamoto, Takaya; Sangen, Kazuyoshi; Hasegawa, Sunao; Liu, Xun; Mashimo, Tsutomu

    2014-10-01

    Iron meteorites and some M-class asteroids are generally understood to be fragments that were originally part of cores of differentiated planetesimals or part of local melt pools on primitive bodies. The parent bodies of iron meteorites may have formed in the terrestrial planet region, from which they were then scattered into the main belt (Bottke, W.F., Nesvorný, D., Grimm, R.E., Morbidelli, A., O'Brien, D.P. [2006]. Nature 439, 821-824). Therefore, a wide range of collisional events at different mass scales, temperatures, and impact velocities would have occurred between the time when the iron was segregated and the impact that eventually exposed the iron meteorites to interplanetary space. In this study, we performed impact disruption experiments of iron meteorite specimens as projectiles or targets at room temperature to increase understanding of the disruption process of iron bodies in near-Earth space. Our iron specimens (as projectiles or targets) were almost all smaller in size than their counterparts (as targets or projectiles, respectively). Experiments of impacts of steel specimens were also conducted for comparison. The fragment mass distribution of the iron material was different from that of rocks. In the iron fragmentation, a higher percentage of the mass was concentrated in larger fragments, probably due to the ductile nature of the material at room temperature. The largest fragment mass fraction f was dependent not only on the energy density but also on the size d of the specimen. We assumed a power-law dependence of the largest fragment mass fraction to initial peak pressure P0 normalized by a dynamic strength, Y, which was defined to be dependent on the size of the iron material. A least squares fit to the data of iron meteorite specimens resulted in the following relationship: f∝∝d, indicating a large size dependence of f. Additionally, the deformation of the iron materials in high-velocity shots was found to be most significant when the

  18. Projected Near-Earth Object Discovery Performance of the Large Synoptic Survey Telescope

    Science.gov (United States)

    Chesley, Steven R.; Veres, Peter

    2017-01-01

    This report describes the methodology and results of an assessment study of the performance of the Large Synoptic Survey Telescope (LSST) in its planned efforts to detect and catalog near-Earth objects (NEOs).

  19. Asteroid Photometry

    CERN Document Server

    Li, Jian-Yang; Buratti, Bonnie J; Takir, Driss; Clark, Beth Ellen

    2015-01-01

    Asteroid photometry has three major applications: providing clues about asteroid surface physical properties and compositions, facilitating photometric corrections, and helping design and plan ground-based and spacecraft observations. The most significant advances in asteroid photometry in the past decade were driven by spacecraft observations that collected spatially resolved imaging and spectroscopy data. In the mean time, laboratory measurements and theoretical developments are revealing controversies regarding the physical interpretations of models and model parameter values. We will review the new developments in asteroid photometry that have occurred over the past decade in the three complementary areas of observations, laboratory work, and theory. Finally we will summarize and discuss the implications of recent findings.

  20. Flying Through Dust From Asteroids

    Science.gov (United States)

    Kohler, Susanna

    2016-11-01

    How can we tell what an asteroid is made of? Until now, weve relied on remote spectral observations, though NASAs recently launched OSIRIS-REx mission may soon change this by landing on an asteroid and returning with a sample.But what if we could learn more about the asteroids near Earth without needing to land on each one? It turns out that we can by flying through their dust.The aerogel dust collector of the Stardust mission. [NASA/JPL/Caltech]Ejected CluesWhen an airless body is impacted by the meteoroids prevalent throughout our solar system, ejecta from the body are flung into the space around it. In the case of small objects like asteroids, their gravitational pull is so weak that most of the ejected material escapes, forming a surrounding cloud of dust.By flying a spacecraft through this cloud, we could perform chemical analysis of the dust, thereby determining the asteroids composition. We could even capture some of the dust during a flyby (for example, by using an aerogel collector like in the Stardust mission) and bring it back home to analyze.So whats the best place to fly a dust-analyzing or -collecting spacecraft? To answer this, we need to know what the typical distribution of dust is around a near-Earth asteroid (NEA) a problem that scientists Jamey Szalay (Southwest Research Institute) and Mihly Hornyi (University of Colorado Boulder) address in a recent study.The colors show the density distribution for dust grains larger than 0.3 m around a body with a 10-km radius. The distribution is asymmetric, with higher densities on the apex side, shown here in the +y direction. [Szalay Hornyi 2016]Moon as a LaboratoryTo determine typical dust distributions around NEAs, Szalay and Hornyi first look at the distribution of dust around our own Moon, caused by the same barrage of meteorites wed expect to impact NEAs. The Moons dust cloud was measured in situ in 2013 and 2014 by the Lunar Dust Experiment (LDEX) on board the Lunar Atmosphere and Dust Environment

  1. Evolution History of Asteroid Itokawa Based on Block Distribution Analysis

    Science.gov (United States)

    Mazrouei, Sara; Daly, Michael; Barnouin, Olivier; Ernst, Carolyn

    2013-04-01

    This work investigates trends in the global and regional distribution of blocks on asteroid 25143 Itokawa in order to discover new findings to better understand the history of this asteroid. Itokawa is a near-Earth object, and the first asteroid that was targeted for a sample return mission. Trends in block population provide new insights in regards to Itokawa's current appearance following the disruption of a possible parent body, and how its surface might have changed since then. Here blocks are defined as rocks or features with distinctive positive relief that are larger than a few meters in size. The size and distribution of blocks are measured by mapping the outline of the blocks using the Small Body Mapping Tool (SBMT) created by the Johns Hopkins University Applied Physics Laboratory [1]. The SBMT allows the user to overlap correctly geo-located Hayabusa images [2] onto the Itokawa shape model. This study provides additional inferences on the original disruption and subsequent re-accretion of Itokawa's "head" and "body" from block analyses. A new approach is taken by analyzing the population of blocks with respect to latitude for both Itokawa's current state, and a hypothetical elliptical body. Itokawa currently rotates approximately about its maximum moment of inertia, which is expected due to conservation of momentum and minimum energy arguments. After the possible disruption of the parent body of Itokawa, the "body" of Itokawa would have tended to a similar rotation. The shape of this body is made by removing the head of Itokawa and applying a semispherical cap. Using the method of [3] inertial properties of this object are calculated. With the assumption that this object had settled to its stable rotational axis, it is found that the pole axis could have been tilted about 13° away from the current axis in the direction opposite the head, equivalent to a 33 meter change in the center of mass. The results of this study provide means to test the hypothesis

  2. 5m Main Belt Asteroid Population Estimation Using Vesta Imagery

    Science.gov (United States)

    Rynders, Michael; Trilling, David E.

    2016-10-01

    The Main Belt is the largest source of Near-Earth asteroids, but objects 2 pixels in diameter that were counted in a 33km 2 region to give a crater density. By knowing the crater density and making some reasonable assumptions about the orbital distribution of asteroids and the age of Vesta's surface, an estimate of the population of small asteroids in the inner main belt was made. It was found that the inner region of the main asteroid belt contains approximately 20 billion asteroids larger than 5 m. These results agree well with the measured inner Main Belt Size distribution derived by the Wide-field Infrared Survey Explorer, WISE (Masiero et al. 2011).

  3. Visual and near-IR spectrophotometry of asteroids

    Science.gov (United States)

    Lebofsky, Larry A.

    1991-01-01

    We have been continuing our studies of the spectral properties of dark asteroids in the solar system. From these studies we expect to learn about the distribution of volatile materials, such as water in clay materials (water of hydration) and how the asteroids may relate to the comets. Our most recent work has been concentrating on simultaneous visual and near infrared photometry near Earth, main belt, and trojan asteroids. We have made observations of some unusual asteroids such as Chiron, which has recently shown cometary activity, and 944 Hidalgo, which has a comet-like orbit. We have also begun studies of the small, dark satellites of Mars and Jupiter in order to understand better how they may relate to the steroids. Could they actually be captured asteroids or comets?

  4. Rotational properties of the Maria asteroid family

    Science.gov (United States)

    Kim, M.; Choi, Y.; Moon, H.; Byun, Y.; Brosch, N.; Kaplan, M.; Kaynar, S.; Uysal, O.; Guzel, E.; Behrend, R.; Yoon, J.; Mottola, S.; Hellmich, S.; Hinse, T.; Eker, Z.; Park, J.

    2014-07-01

    Introduction: The Maria family is regarded as an old-type (˜3 ± 1 Gyr) [1] asteroid family which has experienced substantial collisional and dynamical evolution in the main belt. It is located near the 3:1 Jupiter mean-motion resonance area that supplies near-Earth asteroids (NEAs) to the inner Solar System. Observations: We carried out observations of Maria family asteroids in 134 nights from July 2008 to May 2013 using 0.5-m to 2-m class telescopes at seven observatories in the northern hemisphere, and derived synodic rotational periods for 51 objects, including new periods for 34 asteroids [2]. Results: We found that there is a significant excess of fast and slow rotators in the observed rotation-rate distribution. From the correlations among rotational periods, the amplitudes of lightcurves, and the sizes, we conclude that the rotational properties of the Maria family asteroids have been changed considerably by non-gravitational forces such as the YORP effect. Using the lightcurve inversion method [3,4], we successfully determined pole orientations for 13 Maria members, and found an excess of prograde spins over retrograde spins with a ratio (N_p/N_r) of 3. This implies that the retrograde rotators could have been ejected by the 3:1 resonance into the inner Solar System since the formation of the Maria family. We estimate that approximately 37 to 75 Maria family asteroids larger than 1 km have entered the near-Earth space as per 100 Myr [2].

  5. The Near Earth Object Surveillance Satellite: Mission status and CCD evolution after 18 months on-orbit

    Science.gov (United States)

    Wallace, B.; Scott, R.; Sale, M.

    2014-09-01

    The Near Earth Object Surveillance Satellite (NEOSSat) is a small telescope equipped microsatellite designed to perform both Space Situational Awareness (SSA) experiments and asteroid detection. NEOSSat was launched on 25 February 2013, however, due to time pressures, NEOSSat was launched with only the minimal software required to keep the spacecraft safe. The time pressure also resulted in the spacecraft undergoing reduced system and environmental testing on the ground. The full software suite, required to obtain imagery and maintain stable pointing, has since been uploaded to the spacecraft. NEOSSat has obtained imagery since June 2013, with the shutter both open and closed, but as of March 2014 has not achieved the fine pointing required to obtain scientifically useful data. The collected imagery is being used to characterize the on-board CCD camera. While gain and dark current values agree with pre-launch values, unexpected artefacts have appeared in the images. Methods for mitigating the artefacts through image processing have been developed, and spacecraft-level fixes are currently being investigated. In addition, damage from high energy particles impacting the CCD has produced hot pixels in imagery. We have been able to measure the evolution of these hot pixels over several months, both in terms of numbers and characteristics; these results will be presented. In addition, early results from the mission (image quality issues and evolution, early imagery examples), as well as the mission status (including fine pointing), will be discussed.

  6. High-fidelity Simulations of the Near-Earth Object Search Performance of the Large Synoptic Survey Telescope

    Science.gov (United States)

    Vereš, Peter; Chesley, Steven R.

    2017-07-01

    We perform high-fidelity simulations of a wide-field telescopic survey searching for Near-Earth Objects (NEOs) larger than 140 m, focusing on the observation and detection model, as well as detection efficiency and accuracy. As a test survey, we select the Large Synoptic Survey Telescope (LSST). We use its proposed pointings for a 10-year mission, and model the detection of NEOs in the fields. We discuss individual model parameters for magnitude losses, vignetting, fading, asteroid rotation and colors, fill factor, limiting magnitude, rate of motion, field shape and rotation, and survey patterns. We assess results in terms of the cumulative completeness of the detected population as a function of size and time. Additionally, we examine the sources of modeling uncertainty, and derive the overall NEO population completeness for the baseline LSST survey to be 55 ± 5% for NEOs with absolute magnitude brighter than 22. Including already discovered objects and ongoing surveys, the NEO completeness at the end of the LSST baseline survey should reach ˜77%.

  7. Asteroid Redirect Mission Proximity Operations for Reference Target Asteroid 2008 EV5

    Science.gov (United States)

    Reeves, David M.; Mazanek, Daniel D.; Cichy, Benjamin D.; Broschart, Steve B.; Deweese, Keith D.

    2016-01-01

    NASA's Asteroid Redirect Mission (ARM) is composed of two segments, the Asteroid Redirect Robotic Mission (ARRM), and the Asteroid Redirect Crewed Mission (ARCM). In March of 2015, NASA selected the Robotic Boulder Capture Option1 as the baseline for the ARRM. This option will capture a multi-ton boulder, (typically 2-4 meters in size) from the surface of a large (greater than approx.100 m diameter) Near-Earth Asteroid (NEA) and return it to cis-lunar space for subsequent human exploration during the ARCM. Further human and robotic missions to the asteroidal material would also be facilitated by its return to cis-lunar space. In addition, prior to departing the asteroid, the Asteroid Redirect Vehicle (ARV) will perform a demonstration of the Enhanced Gravity Tractor (EGT) planetary defense technique2. This paper will discuss the proximity operations which have been broken into three phases: Approach and Characterization, Boulder Capture, and Planetary Defense Demonstration. Each of these phases has been analyzed for the ARRM reference target, 2008 EV5, and a detailed baseline operations concept has been developed.

  8. Metalliferous asteroids as potential sources of precious metals

    Science.gov (United States)

    Kargel, Jeffrey S.

    1994-10-01

    Recent discoveries of near-Earth asteroids (NEAs) and chemical analyses of fragments of asteroids (meteorites) suggest that there may be a gold mine, literally, in near-Earth space. Judged from meteorite analyses, two types of asteroids offer particularly bright prospects for recovery of large quantities of precious metals (defined as Au, Pt, Ir, Os, Pd, Rh, and Ru), the ordinary LL chondrites, which contain 1.2-5.3% Fe-Ni metal containing 50-220 ppm of precious metals, and metallic asteroids, which consist almost wholly of Fe-Ni phases and contain variable amounts of precious metals up to several hundred ppm. The pulverized regolith of LL chondrite asteroids could be electromagnetically raked to separate the metallic grains. Suitable metallic asteroids could be processed in their entirety. Statistically, there should be approximately six metallic NEAs larger than 1 km in diameter that contain over 100 ppm of precious metals. Successful recovery of 400,000 tons or more of precious metals contained in the smallest and least rich of these metallic NEAs could yield products worth $5.1 trillion (US) at recent market prices.

  9. IMF dependence of energetic oxygen and hydrogen ion distributions in the near-Earth magnetosphere

    Science.gov (United States)

    Luo, H.; Kronberg, E. A.; Nykyri, K.; Trattner, K. J.; Daly, P. W.; Chen, G. X.; Du, A. M.; Ge, Y. S.

    2017-05-01

    Energetic ion distributions in the near-Earth plasma sheet can provide important information for understanding the entry of ions into the magnetosphere and their transportation, acceleration, and losses in the near-Earth region. In this study, 11 years of energetic proton and oxygen observations (> 274 keV) from Cluster/Research with Adaptive Particle Imaging Detectors were used to statistically study the energetic ion distributions in the near-Earth region. The dawn-dusk asymmetries of the distributions in three different regions (dayside magnetosphere, near-Earth nightside plasma sheet, and tail plasma sheet) are examined in Northern and Southern Hemispheres. The results show that the energetic ion distributions are influenced by the dawn-dusk interplanetary magnetic field (IMF) direction. The enhancement of ion intensity largely correlates with the location of the magnetic reconnection at the magnetopause. The results imply that substorm-related acceleration processes in the magnetotail are not the only source of energetic ions in the dayside and the near-Earth magnetosphere. Energetic ions delivered through reconnection at the magnetopause significantly affect the energetic ion population in the magnetosphere. We also believe that the influence of the dawn-dusk IMF direction should not be neglected in models of the particle population in the magnetosphere.

  10. IMF dependence of energetic oxygen and hydrogen ion distributions in the near-Earth plasma sheet

    Science.gov (United States)

    Luo, Hao; Kronberg, Elena; Nykyri, Katariina; Daly, Patrick; Chen, Gengxiong; Du, Aimin; Ge, Yasong

    2017-04-01

    Energetic ion distributions in the near-Earth plasma sheet can provide important information for understanding the entry of ions into the magnetosphere, and their transportation, acceleration, and losses in the near-Earth region. In this study, 11 years of energetic proton and oxygen observations (> 100 keV) from Cluster/RAPID were used to statistically study the energetic ion distributions in the near-Earth region. The dawn-dusk asymmetries of the distributions in three different regions (dayside magnetosphere, near-Earth nightside plasma sheet, and tail plasma sheet) are examined in northern and southern hemispheres. The results show that the energetic ion distributions are influenced by the dawn-dusk IMF direction. The enhancement of intensity largely correlates with the location of the magnetic reconnection at the magnetopause and the consequent formation of a diamagnetic cavity in the same quadrant of the magnetosphere. The results imply that substorm-related processes in the magnetotail are not the only source of energetic ions in the dayside and the near-Earth plasma sheet. We propose that large-scale cusp diamagnetic cavities can be an additional source and can thus significantly affect the energetic ion population in the magnetosphere. We also believe that the influence of the dawn-dusk IMF direction should not be neglected in models of the particle population in the magnetosphere.

  11. Dynamic Processes of Cross-Tail Current in the Near-Earth Magnetotail

    Institute of Scientific and Technical Information of China (English)

    LU Xing-Qiang; MA Zhi-Wei

    2009-01-01

    Current dynamic processes in realistic magnetotail geometry are studied by Hall magnetohydrodynamic (MHD)simulations under various driven conditions and Hall effects. Associated with the external driving force, a thin current sheet with a broad extent is built up in the near-Earth magnetotail. The time evolution for the formation of the current sheet comprises two phases: slow growth and a fast impulsive phase before the near-Earth disruption of the current sheet resulting from the fast magnetic reconnection. The simulation results indicate that as the external driving force increases, the site and the tailward speed of the near-Earth current disruption region are closer to the Earth and faster, respectively. Whether the near-Earth disruption of the current sheet takes place or not is mainly controlled by Hall effects. It is found that there is no sudden disruption of the current sheet in the near-Earth region if the ion inertial length is below di = 0.04.

  12. Solar wind tans young asteroids

    Science.gov (United States)

    2009-04-01

    's surface composition is an important factor in how red its surface can become. After the first million years, the surface "tans" much more slowly. At that stage, the colour depends more on composition than on age. Moreover, the observations reveal that collisions cannot be the main mechanism behind the high proportion of "fresh" surfaces seen among near-Earth asteroids. Instead, these "fresh-looking" surfaces may be the results of planetary encounters, where the tug of a planet has "shaken" the asteroid, exposing unaltered material. Thanks to these results, astronomers will now be able to understand better how the surface of an asteroid -- which often is the only thing we can observe -- reflects its history. More information This result was presented in a paper published this week in the journal Nature, "Solar wind as the origin of rapid reddening of asteroid surfaces", by P. Vernazza et al. The team is composed of Pierre Vernazza (ESA), Richard Binzel (MIT, Cambridge, USA), Alessandro Rossi (ISTI-CNR, Pisa, Italy), Marcello Fulchignoni (Paris Observatory, France), and Mirel Birlan (IMCCE, CNRS-8028, Paris Observatory, France). A PDF file can be downloaded here. Notes [1] Meteorites are small fragments of asteroids that fall on Earth. While a meteorite enters the Earth's atmosphere its surface can melt and be partially charred by the intense heat. Nevertheless, the meteorite interior remains unaffected, and can be studied in a laboratory, providing a wealth of information on the nature and composition of asteroids. [2] An asteroid family is a group of asteroids that are on similar orbits around the Sun. The members of a given family are believed to be the fragments of a larger asteroid that was destroyed during a collision. [3] The surface of an asteroid is affected by the highly energetic particles forming the solar wind. These particles partially destroy the molecules and crystals on the surface, re-arranging them in other combinations. Over time, these changes give

  13. Asteroid taxonomy

    Science.gov (United States)

    Tholen, David J.; Barucci, M. Antonietta

    1989-01-01

    The spectral reflectivity of asteroid surfaces over the wavelength range of 0.3 to 1.1 micron can be used to classify these objects into several broad groups with similar spectral characteristics. The three most recently developed taxonomies group the asteroids into 9, 11, or 14 different clases, depending on the technique used to perform the analysis. The distribution of the taxonomic classes shows that darker and redder objects become more dominant at larger heliocentric distances, while the rare asteroid types are found more frequently among the small objects of the planet-crossing population.

  14. Digital Tracking Observations Can Discover Asteroids Ten Times Fainter than Conventional Searches

    CERN Document Server

    Heinze, Aren; Trollo, Joseph

    2015-01-01

    We describe digital tracking, a method for asteroid searches that greatly increases the sensitivity of a telescope to faint unknown asteroids. It has been previously used to detect faint Kuiper Belt objects using the Hubble Space Telescope and large ground-based instruments, and to find a small, fast-moving asteroid during a close approach to Earth. We complement this earlier work by developing digital tracking methodology for detecting asteroids using large-format CCD imagers. We demonstrate that the technique enables the ground-based detection of large numbers of new faint asteroids. Our methodology resolves or circumvents all major obstacles to the large-scale application of digital tracking for finding main belt and near-Earth asteroids. We find that for both asteroid populations, digital tracking can deliver a factor of ten improvement over conventional searches. Digital tracking has long been standard practice for deep Kuiper Belt surveys, but even there our methodology enables deeper integrations than ...

  15. A fast ellipsoid model for asteroids inverted from lightcurves

    Institute of Scientific and Technical Information of China (English)

    Xiao-Ping Lu; Hai-Bin Zhao; Zhong You

    2013-01-01

    Research about asteroids has recently attracted more and more attention,especially focusing on their physical structures,such as their spin axis,rotation period and shape.The long distance between observers on Earth and asteroids makes it impossible to directly calculate the shape and other parameters of asteroids,with the exception of Near Earth Asteroids and others that have passed by some spacecrafts.Photometric measurements are still generally the main way to obtain research data on asteroids,i.e.the lightcurves recording the brightness and positions of asteroids.Supposing that the shape of the asteroid is a triaxial ellipsoid with a stable spin,a new method is presented in this article to reconstruct the shape models of asteroids from the lightcurves,together with other physical parameters.By applying a special curvature function,the method calculates the brightness integration on a unit sphere and Lebedev quadrature is employed for the discretization.Finally,the method searches for the optimal solution by the Levenberg-Marquardt algorithm to minimize the residual of the brightness.By adopting this method,not only can related physical parameters of asteroids be obtained at a reasonable accuracy,but also a simple shape model of an ellipsoid can be generated for reconstructing a more sophisticated shape model.

  16. Physical and spectral properties of the Chelyabinsk ordinary chondrite: Support information for future impact deflection missions to asteroids.

    Science.gov (United States)

    Moyano-Cambero, C. E.; Trigo-Rodríguez, J. M.; Pellicer, E.; Llorca, J.; Sort, J.

    2017-03-01

    Asteroids of the near-Earth population experience collisions that disrupte them, producing smaller bodies that can travel from the Main Asteroid Belt to the near-Earth region. Some may survive the entrance through Earth’s atmosphere and become meteorites, that are studied to understand their parent asteroids. The Chelyabinsk superbolide produced a massive meteorite fall, and the pieces recovered can be analyzed to decipher the physical processes affecting the surface of its parent object. On this study we describe the physical properties of Chelyabinsk samples obtained using nanoindentation technique. We also compare ultraviolet to near-infrared spectra of the samples to connect the meteorites with asteroids, considering how impact processing has affected asteroid spectra.

  17. Methodology and Results of the Near-Earth Object (NEO) Human Space Flight (HSF) Accessible Targets Study (NHATS)

    Science.gov (United States)

    Barbee, Brent; Mink, Ronald; Adamo, Daniel

    2011-01-01

    Near-Earth Asteroids (NEAs) have been identified by the current administration as potential destinations for human explorers during the mid-2020s. While the close proximity of these objects' orbits to Earth's orbit creates a risk of highly damaging or catastrophic impacts, it also makes some of these objects particularly accessible to spacecraft departing Earth, and this presents unique opportunities for solar system science and humanity's first ventures beyond cislunar space. Planning such ambitious missions first requires the selection of potentially accessible targets from the growing population of nearly 7,800 NEAs. To accomplish this, NASA is conducting the Near-Earth Object (NEO) Human Space Flight (HSF) Accessible Targets Study (NHATS). Phase I of the NHATS was executed during September of 2010, and Phase II was completed by early March of 2011. The study is ongoing because previously undetected NEAs are being discovered constantly, which has motivated an effort to automate the analysis algorithms in order to provide continuous monitoring of NEA accessibility. The NHATS analysis process consists of a trajectory filter and a minimum maximum estimated size criterion. The trajectory filter employs the method of embedded trajectory grids to compute all possible ballistic round-trip mission trajectories to every NEA in the Jet Propulsion Laboratory (JPL) Small-Body Database (SBDB) and stores all solutions that satisfy the trajectory filter criteria. An NEA must offer at least one qualifying trajectory solution to pass the trajectory filter. The Phase II NHATS filter criteria were purposely chosen to be highly inclusive, requiring Earth departure date between January 1st, 2015 and December 31st, 2040, total round-trip flight time = 8 days, Earth departure C(sub 3) energy = 30 m. This corresponds to an absolute magnitude H = 30 m. The distributions of osculating heliocentric orbital semi-major axis (a), eccentricity (e), and inclination (i), for those 590 NEAs are

  18. Nanoindenting the Chelyabinsk meteorite to learn about impact deflection effects in asteroids

    OpenAIRE

    Moyano-Cambero, Carles E.; Pellicer, Eva; Trigo-Rodríguez, Josep M.; Williams, Iwan P.; Blum, Jürgen; Michel, Patrick; Küppers, Michael; Martínez-Jiménez, Marina; Lloro, Ivan; Sort, Jordi

    2016-01-01

    The Chelyabinsk meteorite is a highly shocked, low porosity, ordinary chondrite, probably similar to S- or Q-type asteroids. Therefore, nanoindentation experiments on this meteorite allow us to obtain key data to understand the physical properties of near-Earth asteroids. Tests at different length scales provide information about the local mechanical properties of the minerals forming this meteorite: reduced Young's modulus, hardness, elastic recovery, and fracture toughness. Those tests are ...

  19. Probability of Causation for Space Radiation Carcinogenesis Following International Space Station, Near Earth Asteroid, and Mars Missions

    Science.gov (United States)

    Cucinotta, Francis A.; Kim, Myung-Hee Y.; Chappell, Lori J.

    2012-01-01

    Cancer risk is an important concern for International Space Station (ISS) missions and future exploration missions. An important question concerns the likelihood of a causal association between a crew members radiation exposure and the occurrence of cancer. The probability of causation (PC), also denoted as attributable risk, is used to make such an estimate. This report summarizes the NASA model of space radiation cancer risks and uncertainties, including improvements to represent uncertainties in tissue-specific cancer incidence models for never-smokers and the U.S. average population. We report on tissue-specific cancer incidence estimates and PC for different post-mission times for ISS and exploration missions. An important conclusion from our analysis is that the NASA policy to limit the risk of exposure-induced death to 3% at the 95% confidence level largely ensures that estimates of the PC for most cancer types would not reach a level of significance. Reducing uncertainties through radiobiological research remains the most efficient method to extend mission length and establish effective mitigators for cancer risks. Efforts to establish biomarkers of space radiation-induced tumors and to estimate PC for rarer tumor types are briefly discussed.

  20. Near-Infrared Spectroscopy of Warm Spitzer-observed Near-Earth Objects

    NARCIS (Netherlands)

    Thomas, Cristina A.; Emery, J. P.; Trilling, D. E.; Delbo, M.; Hora, J. L.; Mueller, M.

    2013-01-01

    We have completed a spectroscopic observing campaign to complement the ExploreNEOs Warm Spitzer program. ExploreNEOs or “The Warm Spitzer NEO Survey: Exploring the history of the inner Solar System and near-Earth space” was allocated 500 hours over two years (2009-2011) to determine diameters and al

  1. Physical Characterization of Warm Spitzer-observed Near-Earth Objects

    NARCIS (Netherlands)

    Thomas, Cristina A.; Emery, Joshua P.; Trilling, David E.; Delbo, Marco; Hora, Joseph L.; Mueller, Michael

    2014-01-01

    Near-infrared spectroscopy of Near-Earth Objects (NEOs) connects diagnostic spectral features to specific surface mineralogies. The combination of spectroscopy with albedos and diameters derived from thermal infrared observations can increase the scientific return beyond that of the individual datas

  2. The Accuracy of the Warm Spitzer Near-Earth Object Survey

    NARCIS (Netherlands)

    Harris, Alan W.; Mommert, M.; Hora, J. L.; Mueller, M.; Trilling, D. E.; Bhattacharya, B.; Bottke, W. F.; Chesley, S.; Delbo', M.; Emery, J. P.; Fazio, G. G.; Mainzer, A.; Penprase, B.; Smith, H. A.; Spahr, T. B.; Stansberry, J. A.; Thomas, C. A.

    2010-01-01

    We report on observations of near-Earth objects (NEOs) performed with IRAC as part of our on-going (2009-2011) Warm Spitzer NEO survey ("ExploreNEOs"), the primary aim of which is to provide sizes and albedos of some 700 NEOs. The emphasis of the work described here is an assessment of the overall

  3. Near-Earth Magnetic Field Effects of Large-Scale Magnetospheric Currents

    DEFF Research Database (Denmark)

    Lühr, Hermann; Xiong, Chao; Olsen, Nils

    2017-01-01

    Magnetospheric currents play an important role in the electrodynamics of near-Earth space. This has been the topic of many space science studies. Here we focus on the magnetic fields they cause close to Earth. Their contribution to the geomagnetic field is the second largest after the core field...

  4. Near-Infrared Spectroscopy of Warm Spitzer-observed Near-Earth Objects

    NARCIS (Netherlands)

    Thomas, Cristina A.; Emery, J. P.; Trilling, D. E.; Delbo, M.; Hora, J. L.; Mueller, M.

    2013-01-01

    We have completed a spectroscopic observing campaign to complement the ExploreNEOs Warm Spitzer program. ExploreNEOs or “The Warm Spitzer NEO Survey: Exploring the history of the inner Solar System and near-Earth space” was allocated 500 hours over two years (2009-2011) to determine diameters and

  5. Rotational properties of Maria asteroid family

    CERN Document Server

    Kim, Myung-Jin; Moon, Hong-Kyu; Byun, Yong-Ik; Brosch, Noah; Kaplan, Murat; Kaynar, Suleyman; Uysal, Omer; Guzel, Eda; Behrend, Raoul; Yoon, Joh-Na; Mottola, Stefano; Hellmich, Stephan; Hinse, Tobias C; Eker, Zeki; Park, Jang-Hyun

    2013-01-01

    Maria family is regarded as an old-type (~3 +/- 1 Gyr) asteroid family which has experienced substantial collisional and dynamical evolution in the Main-belt. It is located nearby the 3:1 Jupter mean motion resonance area that supplies Near-Earth asteroids (NEAs) to the inner Solar System. We carried out observations of Maria family asteroids during 134 nights from 2008 July to 2013 May, and derived synodic rotational periods for 51 objects, including newly obtained periods of 34 asteroids. We found that there is a significant excess of fast and slow rotators in observed rotation rate distribution. The two-sample Kolmogorov-Smirnov test confirms that the spin rate distribution is not consistent with a Maxwellian at a 92% confidence level. From correlations among rotational periods, amplitudes of lightcurves, and sizes, we conclude that the rotational properties of Maria family asteroids have been changed considerably by non-gravitational forces such as the YORP effect. Using a lightcurve inversion method (Kaa...

  6. Thermal Tomography of Asteroid Surface Structure

    CERN Document Server

    Harris, Alan

    2016-01-01

    Knowledge of the surface thermal inertia of an asteroid can provide insight into surface structure: porous material has a lower thermal inertia than rock. We develop a means to estimate thermal inertia values of asteroids and use it to show that thermal inertia appears to increase with spin period in the case of main-belt asteroids (MBAs). Similar behavior is found on the basis of thermophysical modeling for near-Earth objects (NEOs). We interpret our results in terms of rapidly increasing material density and thermal conductivity with depth, and provide evidence that thermal inertia increases by factors of 10 (MBAs) to 20 (NEOs) within a depth of just 10 cm. Our results are consistent with a very general picture of rapidly changing material properties in the topmost regolith layers of asteroids and have important implications for calculations of the Yarkovsky effect, including its perturbation of the orbits of potentially hazardous objects and those of asteroid family members after the break-up event. Eviden...

  7. Thermal Tomography of Asteroid Surface Structure

    Science.gov (United States)

    Harris, Alan W.; Drube, Line

    2016-12-01

    Knowledge of the surface thermal inertia of an asteroid can provide insight into its surface structure: porous material has a lower thermal inertia than rock. We develop a means to estimate thermal inertia values of asteroids and use it to show that thermal inertia appears to increase with spin period in the case of main-belt asteroids (MBAs). Similar behavior is found on the basis of thermophysical modeling for near-Earth objects (NEOs). We interpret our results in terms of rapidly increasing material density and thermal conductivity with depth, and provide evidence that thermal inertia increases by factors of 10 (MBAs) to 20 (NEOs) within a depth of just 10 cm. Our results are consistent with a very general picture of rapidly changing material properties in the topmost regolith layers of asteroids and have important implications for calculations of the Yarkovsky effect, including its perturbation of the orbits of potentially hazardous objects and those of asteroid family members after the break-up event. Evidence of a rapid increase of thermal inertia with depth is also an important result for studies of the ejecta-enhanced momentum transfer of impacting vehicles (“kinetic impactors”) in planetary defense.

  8. Asteroid thermal modeling in the presence of reflected sunlight

    Science.gov (United States)

    Myhrvold, Nathan

    2016-10-01

    This study addresses thermal modeling of asteroids with a new derivation of the Near Earth Asteroid Thermal (NEATM) model which correctly accounts for the presence of reflected sunlight in short wave IR bands. Kirchhoff's law of thermal radiation applies to this case and has important implications. New insight is provided into the ???? parameter in the NEATM model and it is extended to thermal models besides NEATM. The role of surface material properties on ???? is examined using laboratory spectra of meteorites and other asteroid compositional proxies; the common assumption that emissivity ????=0.9 in asteroid thermal models may not be justified and can lead to misestimating physical parameters. In addition, indeterminacy in thermal modeling can limit its ability to uniquely determine temperature and other physical properties. A new curve-fitting approach allows thermal modeling to be done independently of visible-band observational parameters, such as the absolute magnitude ????.

  9. MarcoPolo-R: Asteroid Sample Return Mission

    Science.gov (United States)

    Brucato, John Robert

    2012-07-01

    MarcoPolo-R is a sample return mission to a primitive Near-Earth Asteroid (NEA) selected for the assessment study in the framework of ESA Cosmic Vision 2015-25 program. MarcoPolo-R is an European-led mission with a proposed NASA contribution. MarcoPolo-R will rendezvous with a primitive carbon-rich NEA, scientifically characterize it at multiple scales, and return a unique sample to Earth unaltered by the atmospheric entry process or terrestrial weathering. The baseline target is a binary asteroid (175706) 1996 FG3, which offers a very efficient operational and technical mission profile. A binary target also provides enhanced science return. The choice of this target will allow new investigations to be performed more easily than at a single object, and also enables investigations of the fascinating geology and geophysics of asteroids that are impossible at a single object. Several launch windows have been identified in the time-span 2020-2024. The baseline mission scenario of MarcoPolo-R to 1996 FG3 foresees a single primary spacecraft, carrying the Earth re-entry capsule and sample acquisition and transfer system, launched by a Soyuz-Fregat rocket from Kourou. The scientific payload includes state-of-the-art instruments, e.g. a camera system for high resolution imaging from orbit and on the surface, spectrometers covering visible, near-infrared and mid-infrared wavelengths, a neutral-particle analyser, a radio science experiment and optional laser altimeter. If resources are available, an optional Lander will be added to perform in-situ characterization close to the sampling site, and internal structure investigations. MarcoPolo-R will allow us to study the most primitive materials available to investigate early solar system formation processes. The main goal of the MarcoPolo-R mission is to return unaltered NEA material for detailed analysis in ground-based laboratories. Only in the laboratory can instruments with the necessary precision and sensitivity be

  10. Earth resonant gravity assists for asteroid retrieval missions

    OpenAIRE

    Sanchez, J. P.; E. M. Alessi; D. G. Yarnoz; McInnes, C.R.

    2013-01-01

    Asteroids and comets are of strategic importance for science in an effort to uncover the formation, evolution and composition of the Solar System. Near-Earth objects (NEOs) are of particular interest because of their accessibility from Earth, but also because of their speculated wealth of material resources. The possibility of retrieving entire NEOs from accessible heliocentric orbits and moving them into the Earth’s neighbourhood is today a credible possibility considered by NASA, within its...

  11. The Near Earth Object Scout Spacecraft: A Low Cost Approach to in-situ Characterization of the NEO Population

    Science.gov (United States)

    Koontz, Steven L.; Condon, Gerald; Graham, Lee; Bevilacqua, Ricardo

    2014-01-01

    In this paper we describe a micro/nano satellite spacecraft and a supporting mission profile and architecture designed to enable preliminary in-situ characterization of a significant number of Near Earth Objects (NEOs) at reasonable cost. The spacecraft will be referred to as the NEO Scout. NEO Scout spacecraft are to be placed in GTO, GEO, or cis-lunar space as secondary payloads on launch vehicles headed for GTO or beyond and will begin their mission after deployment from the launcher. A distinguishing key feature of the NEO scout system is to design the mission timeline and spacecraft to rendezvous with and land on the target NEOs during close approach to the Earth-Moon system using low-thrust/high- impulse propulsion systems. Mission feasibility and preliminary design analysis are presented along with detailed trajectory calculations. The use of micro/nano satellites in low-cost interplanetary exploration is attracting increasing attention and is the subject of several annual workshops and published design studies (1-4). The NEO population consists of those asteroids and short period comets orbiting the Sun with a perihelion of 1.3 astronomical units or less (5-8). As of July 30, 2013 10065 Near-Earth objects have been discovered. The spin rate, mass, density, surface physical (especially mechanical) properties, composition, and mineralogy of the vast majority of these objects are highly uncertain and the limited available telescopic remote sensing data imply a very diverse population (5-8). In-situ measurements by robotic spacecraft are urgently needed to provide the characterization data needed to support hardware and mission design for more ambitious human and robotic NEO operations. Large numbers of NEOs move into close proximity with the Earth-Moon system every year (9). The JPL Near-Earth Object Human Space Flight Accessible Targets Study (NHATS) (10) has produced detailed mission profile and delta V requirements for various NEO missions ranging from 30

  12. Power Supply for a Manned International Asteroid Mission

    Science.gov (United States)

    Weingartner, Stefan; Nahra, Henry K.; Kohout, Lisa L.; Larin, Max

    1991-01-01

    A feasibility study considering the exploitation of a near Earth asteroid was performed. The power requirements and proposed power systems for the crew vehicle, cargo vehicles, mining and processing equipment are described. A photovoltaic power system was selected to meet the 52.1 kWe and the 3.9 kWe power requirements of the crew and cargo vehicles, respectively. A nuclear power plant using a thermodynamic Rankine cycle with a total mass of 62.1 tons was chosen to provide the 7.225 MWe and the 5.5 MWth required for the mining and processing activities at the asteroid.

  13. Note about the impact possibilities of asteroid (99942) Apophis

    OpenAIRE

    2010-01-01

    The Monte Carlo method of the nominal orbit clonning was applied to the case of 99942 Apophis, the asteroid from the Aten group. Calculations based on observations from the time interval of 2004 03 15 - 2008 01 09 have shown that the asteroid will pass near Earth in 2029 at the minimum distance of 5.921 \\pm 0.042 R_{Earth}, what implies that the likelihood that Apophis strikes the planet at 2036 April 13 increased to 4.5\\times 10^{-6} (from about 6\\times 10^{-7} previously announced by us in ...

  14. Physical Properties of Asteroid (10302) 1989 ML, a Potential Spacecraft Target, from Spitzer Observations

    NARCIS (Netherlands)

    Mueller, Michael; Harris, A. W.

    2006-01-01

    We report on results from recent Spitzer observations of near-Earth asteroid (10302) 1989 ML, which is among the lowest-ranking objects in terms of the specific momentum Δv required to reach it from Earth. It was originally considered as a target for Hayabusa and is now under consideration as a targ

  15. Physical Properties of Asteroid (10302) 1989 ML, a Potential Spacecraft Target, from Spitzer Observations

    NARCIS (Netherlands)

    Mueller, Michael; Harris, A. W.

    2006-01-01

    We report on results from recent Spitzer observations of near-Earth asteroid (10302) 1989 ML, which is among the lowest-ranking objects in terms of the specific momentum Δv required to reach it from Earth. It was originally considered as a target for Hayabusa and is now under consideration as a

  16. Towards understanding the dynamical evolution of asteroid 25143 Itokawa: constraints from sample analysis

    National Research Council Canada - National Science Library

    Connolly Jr, Harold C; Lauretta, Dante S; Walsh, Kevin J; Tachibana, Shogo; Bottke Jr, William F

    2015-01-01

    ..., and the dynamical history of the asteroid from the main belt to near-Earth space. We synthesize existing data to pose hypotheses to be tested by dynamical modeling and the analyses of future samples returned by Hayabusa 2 and OSIRIS-REx...

  17. Physical Properties of Asteroid (10302) 1989 ML, a Potential Spacecraft Target, from Spitzer Observations

    NARCIS (Netherlands)

    Mueller, Michael; Harris, A. W.

    2006-01-01

    We report on results from recent Spitzer observations of near-Earth asteroid (10302) 1989 ML, which is among the lowest-ranking objects in terms of the specific momentum Δv required to reach it from Earth. It was originally considered as a target for Hayabusa and is now under consideration as a targ

  18. Analysis of ejecta fate from proposed man-made impactors into near-Earth objects --- a NEOShield study

    Science.gov (United States)

    Schwartz, S.; Michel, P.; Jutzi, M.

    2014-07-01

    Asteroids measuring 100 meters across tend to impact the Earth once every 5,000 years on average [1]. Smaller bodies enter into the Earth's atmosphere more frequently, but may detonate before reaching the surface. Conversely, impacts from larger bodies are more rare [2], but can come with devastating global consequences to living species. In 2005, a United States Congressional mandate called for NASA to detect, by 2020, 90 percent of near-Earth objects (NEOs) having diameters of 140 meters or greater [3]. One year prior, ESA's Near-Earth Object Mission Advisory Panel (NEOMAP) recommended the study of a kinetic impactor mission as a priority in the framework of NEO risk assessment [4]. A ''Phase-A'' study of such a mission, Don Quixote, took place at ESA until 2007. In accordance with NEOMAP and with the Target NEO Global Community's recommendations in 2011 [5], the NEOShield Project is being funded for 3.5 years by the European Commission in its FP7 program. NEOShield began in 2012 and is primarily, but not exclusively, a European consortium of research institutions and engineering industries that aims to analyze promising mitigation options and provide solutions to the critical scientific and technical obstacles involved in confronting threats posed by the small bodies in the neighborhood of the Earth's orbit [6]. To further explore the NEO threat mitigation via the strategy of kinetic impact, building upon the Don Quixote study, the idea is to target a specific NEO for impact and attempt to quantify the response. How long do ejecta remain aloft and where do they end up? Fragments that are ejected at high speeds escape, but what about material moving at or near the escape speed of the NEO or that suffer energy-dissipating collisions after being ejected? Where would be a ''safe'' location for an observing spacecraft during and subsequent to the impact? Here, we outline the early phases of an ongoing numerical investigation of the fate of the material ejected from a

  19. Optimised low-thrust mission to the Atira asteroids

    Science.gov (United States)

    Di Carlo, Marilena; Romero Martin, Juan Manuel; Ortiz Gomez, Natalia; Vasile, Massimiliano

    2017-04-01

    Atira asteroids are recently-discovered celestial bodies characterised by orbits lying completely inside the heliocentric orbit of the Earth. The study of these objects is difficult due to the limitations of ground-based observations: objects can only be detected when the Sun is not in the field of view of the telescope. However, many asteroids are expected to exist in the inner region of the Solar System, many of which could pose a significant threat to our planet. In this paper, a small, low-cost, mission to visit the known Atira asteroids and to discover new Near Earth Asteroids (NEA) is proposed. The mission is realised using electric propulsion. The trajectory is optimised to maximise the number of visited asteroids of the Atira group using the minimum propellant consumption. During the tour of the Atira asteroids an opportunistic NEA discovery campaign is proposed to increase our knowledge of the asteroid population. The mission ends with a transfer to an orbit with perihelion equal to Venus's orbit radius. This orbit represents a vantage point to monitor and detect asteroids in the inner part of the Solar System and provide early warning in the case of a potential impact.

  20. Matching asteroid population characteristics with a model constructed from the YORP-induced rotational fission hypothesis

    CERN Document Server

    Jacobson, Seth Andrew; Rossi, Alessandro; Scheeres, Daniel J

    2016-01-01

    From the results of a comprehensive asteroid population evolution model, we conclude that the YORP-induced rotational fission hypothesis can be consistent with the observed population statistics of small asteroids in the main belt including binaries and contact binaries. The foundation of this model is the asteroid rotation model of Marzari et al. (2011), which incorporates both the YORP effect and collisional evolution. This work adds to that model the rotational fission hypothesis and the binary evolution model of Jacobson & Scheeres (2011). The asteroid population evolution model is highly constrained by these and other previous works, and therefore it has only two significant free parameters: the ratio of low to high mass ratio binaries formed after rotational fission events and the mean strength of the binary YORP (BYORP) effect. We successfully reproduce characteristic statistics of the small asteroid population: the binary fraction, the fast binary fraction, steady-state mass ratio fraction and the...

  1. Spins, shapes, and orbits for potentially hazardous near-earth objects by NEON

    DEFF Research Database (Denmark)

    Muinonen, K.; Jørgensen, U.G.

    2006-01-01

    radiative transfer, scattering, celestial mechanics, methods: analytical, methods: data analysis, methods: numerical, methods: statistical, techniques: photometric, astrometry, comets: general, minor planets, asteroids......radiative transfer, scattering, celestial mechanics, methods: analytical, methods: data analysis, methods: numerical, methods: statistical, techniques: photometric, astrometry, comets: general, minor planets, asteroids...

  2. The Asteroid Impact and Deflection Assessment (AIDA) mission: Science Proximity Operations

    Science.gov (United States)

    Barnouin, Olivier; Bellerose, Julie; Carnelli, Ian; Carrol, Kieran; Ciarletti, Valérie; Cheng, Andrew F.; Galvez, Andres; Green, Simon F.; Grieger, Bjorn; Hirabayashi, Masatoshi; Herique, Alain; Kueppers, Michael; Minton, David A.; Mellab, Karim; Michel, Patrick; Rivkin, Andrew S.; Rosenblatt, Pascal; Tortora, Paolo; Ulamec, Stephan; Vincent, Jean-Baptiste; Zannoni, Marco

    2016-10-01

    The moon of the near-Earth binary asteroid 65803 Didymos is the target of the Asteroid Impact and Deflection Assessment (AIDA) mission. This mission is a joint effort between NASA and ESA to investigate the effectiveness of a kinetic impactor in deflecting an asteroid. The mission is composed of two components: the NASA-led Double Asteroid Redirect Test (DART) that will impact Didymos' moon (henceforth Didymos B), and the ESA-led Asteroid Impact Mission (AIM) that will survey the Didymos system. Both will undertake proximity operations to characterize the physical and dynamical properties of the Didymos system that are of maximum importance in the joint AIDA mission to understand the factors at play when assessing the mometum transfer that follows DART's impact into Didymos B. Using much of ESA's Rosetta experience, the AIM mission will undertake proximity operations both before and after DART's impact. AIM's chracterization includes measuring the precise orbital configuration, masses, internal properties, surface geology and regolith properties of the primary and secondary, using visible and thermal imaging, radar measurements and radio science data. AIM will also release the small MASCOT-2 lander, as well as a suite of a CubeSats to help achieve these objectives. DART proximity observations include two phases of imaging. The first makes use of a suite of long range images that will add light curve data to what will be collected from Earth. These data will refine the orbit period of Didymos B, and provide constraints for modeling the shape of both Didymos A and B. The second phase begins just under an hour before impact when resolved imaging of the Didymos system provides further shape model constraints for the visble parts of both Didymos A and B, some possible constraints on the mass of Didymos B and key geological information of both objects and the impact site. In this presentation, we will summarize the proximity operations undertaken by both DART and AIM

  3. Discovery, Observational Data and the Orbit of the Amor Group Asteroid 2010 BT3

    Science.gov (United States)

    Černis, K.; Zdanavičius, J.; Wlodarczyk, I.; Stonkutė, E.

    A project devoted to astrometric and photometric observations of asteroids at the Molėtai Observatory is described. One of its most important results is the discovery of the asteroid 2010 BT3 belonging to the Amor group of the near-Earth objects. The results of astrometric and photometric observations of the asteroid are presented. The brightness variations of the asteroid are found to be about 0.2 mag in R. The orbit of the asteroid was computed from 96 observations. This orbit, combined with the apparent brightness, gives the absolute magnitude 21.34 mag and the diameter between 160 m and 360 m, taking albedos of S-type and C-type asteroids, respectively.

  4. Radar Observations of Asteroids

    Science.gov (United States)

    Ostro, S. J.

    2003-05-01

    During the past 25 years, radar investigations have provided otherwise unavailable information about the physical and dynamical properties of more than 200 asteroids. Measurements of the distribution of echo power in time delay and Doppler frequency provide two-dimensional images with spatial resolution as fine as a decameter. Sequences of delay-Doppler images can be used to produce geologically detailed three-dimensional models, to define the rotation state precisely, to constrain the internal density distribution, and to estimate the trajectory of the object's center of mass. Radar wavelengths (4 to 13 cm) and the observer's control of transmitted and received polarizations make the observations sensitive to near-surface bulk density and macroscopic structure. Since delay-Doppler positional measurements are orthogonal to optical angle measurements and typically have much finer fractional precision, they are powerful for refining orbits and prediction ephemerides. Radar astrometry can add decades or centuries to the interval over which an asteroid's close Earth approaches can accurately be predicted and can significantly refine collision probability estimates based on optical astrometry alone. In the highly unlikely case that a small body is on course for an Earth collision in this century, radar reconnaissance would almost immediately distinguish between an impact trajectory and a near miss and would dramatically reduce the difficulty and cost of any effort to prevent the collision. The sizes and rotation periods of radar-detected asteroids span more than four orders of magnitude. These observations have revealed both stony and metallic objects, elongated and nonconvex shapes as well as nearly featureless spheroids, small-scale morphology ranging from smoother than the lunar regolith to rougher than the rockiest terrain on Mars, craters and diverse linear structures, non-principal-axis spin states, contact binaries, and binary systems.

  5. Radar Investigations of Asteroids

    Science.gov (United States)

    Ostro, S.

    2004-05-01

    Radar investigations have provided otherwise unavailable information about the physical and dynamical properties of about 230 asteroids. Measurements of the distribution of echo power in time delay (range) and Doppler frequency (line-of-sight velocity) provide two-dimensional images with spatial resolution as fine as a decameter. Sequences of delay-Doppler images can be used to produce geologically detailed three-dimensional models, to define the rotation state precisely, to constrain the internal density distribution, and to estimate the trajectory of the object's center of mass. Radar wavelengths (4 to 13 cm) and the observer's control of transmitted and received polarizations make the observations sensitive to near-surface bulk density and macroscopic structure. Since delay-Doppler measurements are orthogonal to optical angle measurements and typically have much finer fractional precision, they are powerful for refining orbits and prediction ephemerides. Such astrometric measurements can add decades or centuries to the interval over which an asteroid's close Earth approaches can accurately be predicted and can significantly refine collision probability estimates based on optical astrometry alone. In the highly unlikely case that a small body is on course for an Earth collision in this century, radar reconnaissance would almost immediately distinguish between an impact trajectory and a near miss and would dramatically reduce the difficulty and cost of any effort to prevent the collision. The sizes and rotation periods of radar-detected asteroids span more than four orders of magnitude. The observations have revealed both stony and metallic objects, elongated and nonconvex shapes as well as nearly featureless spheroids, small-scale morphology ranging from smoother than the lunar regolith to rougher than the rockiest terrain on Mars, craters and diverse linear structures, non-principal-axis spin states, contact binaries, and binary systems.

  6. OSIRIS-REx, Returning the Asteroid Sample

    Science.gov (United States)

    Ajluni, Thomas, M.; Everett, David F.; Linn, Timothy; Mink, Ronald; Willcockson, William; Wood, Joshua

    2015-01-01

    This paper addresses the technical aspects of the sample return system for the upcoming Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) asteroid sample return mission. The overall mission design and current implementation are presented as an overview to establish a context for the technical description of the reentry and landing segment of the mission.The prime objective of the OSIRIS-REx mission is to sample a primitive, carbonaceous asteroid and to return that sample to Earth in pristine condition for detailed laboratory analysis. Targeting the near-Earth asteroid Bennu, the mission launches in September 2016 with an Earth reentry date of September 24, 2023.OSIRIS-REx will thoroughly characterize asteroid Bennu providing knowledge of the nature of near-Earth asteroids that is fundamental to understanding planet formation and the origin of life. The return to Earth of pristine samples with known geologic context will enable precise analyses that cannot be duplicated by spacecraft-based instruments, revolutionizing our understanding of the early Solar System. Bennu is both the most accessible carbonaceous asteroid and one of the most potentially Earth-hazardous asteroids known. Study of Bennu addresses multiple NASA objectives to understand the origin of the Solar System and the origin of life and will provide a greater understanding of both the hazards and resources in near-Earth space, serving as a precursor to future human missions to asteroids.This paper focuses on the technical aspects of the Sample Return Capsule (SRC) design and concept of operations, including trajectory design and reentry retrieval. Highlights of the mission are included below.The OSIRIS-REx spacecraft provides the essential functions for an asteroid characterization and sample return mission: attitude control propulsion power thermal control telecommunications command and data handling structural support to ensure successful

  7. Deflection by kinetic impact: Sensitivity to asteroid properties

    Science.gov (United States)

    Bruck Syal, Megan; Michael Owen, J.; Miller, Paul L.

    2016-05-01

    Impacting an asteroid with a spacecraft traveling at high speed delivers an impulsive change in velocity to the body. In certain circumstances, this strategy could be used to deflect a hazardous asteroid, moving its orbital path off of an Earth-impacting course. However, the efficacy of momentum delivery to asteroids by hypervelocity impact is sensitive to both the impact conditions (particularly velocity) and specific characteristics of the target asteroid. Here we numerically model asteroid response to kinetic impactors under a wide range of initial conditions, using an Adaptive Smoothed Particle Hydrodynamics code. Impact velocities spanning 1-30 km/s were investigated, yielding, for a particular set of assumptions about the modeled target material, a power-law dependence consistent with a velocity-scaling exponent of μ = 0.44. Target characteristics including equation of state, strength model, porosity, rotational state, and shape were varied, and corresponding changes in asteroid response were documented. The kinetic-impact momentum-multiplication factor, β, decreases with increasing asteroid cohesion and increasing porosity. Although increased porosity lowers β, larger porosities result in greater deflection velocities, as a consequence of reduced target masses for asteroids of fixed size. Porosity also lowers disruption risk for kinetic impacts near the threshold of disruption. Including fast (P = 2.5 h) and very fast (P = 100 s) rotation did not significantly alter β but did affect the risk of disruption by the impact event. Asteroid shape is found to influence the efficiency of momentum delivery, as local slope conditions can change the orientation of the crater ejecta momentum vector. These results emphasize the need for asteroid characterization studies to bracket the range of target conditions expected at near-Earth asteroids while also highlighting some of the principal uncertainties associated with the kinetic-impact deflection strategy.

  8. Enabling Communication and Navigation Technologies for Future Near Earth Science Missions

    Science.gov (United States)

    Israel, David J.; Heckler, Gregory; Menrad, Robert; Hudiburg, John; Boroson, Don; Robinson, Bryan; Cornwell, Donald

    2016-01-01

    In 2015, the Earth Regimes Network Evolution Study (ERNESt) proposed an architectural concept and technologies that evolve to enable space science and exploration missions out to the 2040 timeframe. The architectural concept evolves the current instantiations of the Near Earth Network and Space Network with new technologies to provide a global communication and navigation network that provides communication and navigation services to a wide range of space users in the near Earth domain. The technologies included High Rate Optical Communications, Optical Multiple Access (OMA), Delay Tolerant Networking (DTN), User Initiated Services (UIS), and advanced Position, Navigation, and Timing technology. This paper describes the key technologies and their current technology readiness levels. Examples of science missions that could be enabled by the technologies and the projected operational benefits of the architecture concept to missions are also described.

  9. The measuring complex for detection of radioactive waste in near-earth space

    Science.gov (United States)

    Ulin, S. E.; Vlasik, K. F.; Grachev, V. M.; Dmitrenko, V. V.; Novikov, A. S.; Uteshev, Z. M.; Shustov, A. E.; Chernishova, I. V.; Bakhtigaraev, N. S.; Rykhlova, L. V.; Kazantsev, S. G.

    2017-01-01

    Description of a measuring complex intended for detection and identification of radioactive waste in the near-earth space is presented. The complex consists of several xenon gamma-ray spectrometers, developed on the base of the thin-walled impulse ionization chamber with sensitive volume of four litres. Their main physics - technical characteristics are considered. An estimation probability for detection of various elements comprising radioactive waste by means of the measuring complex on board the spacecraft “Meteor” is given.

  10. Orbit-Attitude Changes of Objects in Near Earth Space Induced by Natural Charging

    Science.gov (United States)

    2017-05-02

    COVERED (From - To) 21-05-2015 – 21-02-2017 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Orbit- Attitude Changes of Objects in Near Earth Space Induced...charging plasma conditions lead to significant secular perturbations in the investigated cases. 15. SUBJECT TERMS State-of-the Art; Attitude ...non-equilibrium scenario, charging takes place according to the differential equation, ∑ j I j = C dφdt . The time scale for charging of a spherical

  11. NASA's Evolution to Ka-Band Space Communications for Near-Earth Spacecraft

    Science.gov (United States)

    McCarthy, Kevin; Stocklin, Frank; Geldzahler, Barry; Friedman, Daniel; Celeste, Peter

    2010-01-01

    This slide presentation reviews the exploration of NASA using a Ka-band system for spacecraft communications in Near-Earth orbits. The reasons for changing to Ka-band are the higher data rates, and the current (X-band spectrum) is becoming crowded. This will require some modification to the current ground station antennas systems. The results of a Request for Information (RFI) are discussed, and the recommended solution is reviewed.

  12. The Laser Communications Relay and the Path to the Next Generation Near Earth Relay

    Science.gov (United States)

    Israel, David J.

    2015-01-01

    NASA Goddard Space Flight Center is currently developing the Laser Communications Relay Demonstration (LCRD) as a Path to the Next Generation Near Earth Space Communication Network. The current NASA Space Network or Tracking and Data Relay Satellite System is comprised of a constellation of Tracking and Data Relay Satellites (TDRS) in geosynchronous orbit and associated ground stations and operation centers. NASA is currently targeting a next generation of relay capability on orbit in the 2025 timeframe.

  13. Asteroid Redirect Crewed Mission Nominal Design and Performance

    Science.gov (United States)

    Condon, Gerald; williams, Jacob

    2014-01-01

    In 2010, the President announced that, in 2025, the U.S. intended to launch a human mission to an asteroid [1]. This announcement was followed by the idea of a Capability Driven Framework (CDF) [2], which is based on the idea of evolving capabilities from less demanding to more demanding missions to multiple possible destinations and with increased flexibility, cost effectiveness and sustainability. Focused missions, such as a NASA inter-Center study that examined the viability and implications of sending a crew to a Near Earth Asteroid (NEA) [3], provided a way to better understand and evaluate the utility of these CDF capabilities when applied to an actual mission. The long duration of the NEA missions were contrasted with a concept described in a study prepared for the Keck Institute of Space Studies (KISS) [4] where a robotic spacecraft would redirect an asteroid to the Earth-Moon vicinity, where a relatively short duration crewed mission could be conducted to the captured asteroid. This mission concept was included in the National Aeronautics and Space Administration (NASA) fiscal year 2014 budget request, as submitted by the NASA Administrator [5]. NASA studies continued to examine the idea of a crewed mission to a captured asteroid in the Earth-Moon vicinity. During this time was an announcement of NASA's Asteroid Grand Challenge [6]. Key goals for the Asteroid Grand Challenge are to locate, redirect, and explore an asteroid, as well as find and plan for asteroid threats. An Asteroid Redirect Mission (ARM) study was being conducted, which supports this Grand Challenge by providing understanding in how to execute an asteroid rendezvous, capture it, and redirect it to Earth-Moon space, and, in particular, to a distant retrograde orbit (DRO). Subsequent to the returning of the asteroid to a DRO, would be the launch of a crewed mission to rendezvous with the redirected asteroid. This report examines that crewed mission by assessing the Asteroid Redirect Crewed

  14. Effect of upward ion on field-aligned currents in the near-earth magnetotail

    Institute of Scientific and Technical Information of China (English)

    ZHANG; LingQian; LIU; ZhenXing; MA; ZhiWei; SHEN; Chao; ZHOU; XuZhi; ZHANG; XianGuo

    2007-01-01

    A 3-dimensional resistive MHD simulation was carried out to study the effect of the upward ions on the field-aligned currents (FACs) in the near-earth magnetotail. The simulation results show that the up-flow ions originating from the nightside auroral oval would drift into the center plasma sheet along the magnetic field lines in the plasma sheet boundary, and have an important effect on the field-aligned currents. The main conclusions include that: 1) the upward-ions mainly affect the field- aligned currents in the near-earth magnetotail (inside 15 Re); 2) the generated FACs in the near-earth region have two types, i.e., Region 1 FAC in the high-latitude and Region 2 FAC in the low-latitude; 3) FACs increase with the enhancement of the upward ion flux; 4) with the same flux of the upward ions, FACs enhance with the increase of the velocity of the up-flow ions; 5) the intensification of FACs is also closely related with the latitude of the upward ions, and the ions from the closed field line region generate larger FACs; 6) the generation of FACs is closely related with By created by the upward ions.

  15. Defending Planet Earth: Near-Earth Object Surveys and Hazard Mitigation Strategies

    Science.gov (United States)

    2010-01-01

    The United States spends approximately four million dollars each year searching for near-Earth objects (NEOs). The objective is to detect those that may collide with Earth. The majority of this funding supports the operation of several observatories that scan the sky searching for NEOs. This, however, is insufficient in detecting the majority of NEOs that may present a tangible threat to humanity. A significantly smaller amount of funding supports ways to protect the Earth from such a potential collision or "mitigation." In 2005, a Congressional mandate called for NASA to detect 90 percent of NEOs with diameters of 140 meters of greater by 2020. Defending Planet Earth: Near-Earth Object Surveys and Hazard Mitigation Strategies identifies the need for detection of objects as small as 30 to 50 meters as these can be highly destructive. The book explores four main types of mitigation including civil defense, "slow push" or "pull" methods, kinetic impactors and nuclear explosions. It also asserts that responding effectively to hazards posed by NEOs requires national and international cooperation. Defending Planet Earth: Near-Earth Object Surveys and Hazard Mitigation Strategies is a useful guide for scientists, astronomers, policy makers and engineers.

  16. The Mission Accessible Near-Earth Objects Survey (MANOS): spectroscopy results

    Science.gov (United States)

    Thomas, Cristina A.; Moskovitz, Nicholas; Hinkle, Mary L.; Mommert, Michael; Polishook, David; Thirouin, Audrey; Binzel, Richard; Christensen, Eric J.; DeMeo, Francesca E.; Person, Michael J.; Trilling, David E.; Willman, Mark; Burt, Brian

    2016-10-01

    The Mission Accessible Near-Earth Object Survey (MANOS) is an ongoing physical characterization survey to build a large, uniform catalog of physical properties including lightcurves and visible wavelength spectroscopy. We will use this catalog to investigate the global properties of the small NEO population and identify individual objects that can be targets of interest for future exploration. To accomplish our goals, MANOS uses a wide variety of telescopes (1-8m) in both the northern and southern hemispheres. We focus on targets that have been recently discovered and operate on a regular cadence of remote and queue observations to enable rapid characterization of small NEOs. Targets for MANOS are selected based on three criteria: mission accessibility, size, and observability. With our resources, we observe 5-10 newly discovered sub-km NEOs per month. MANOS has been operating for three years and we have observed over 500 near-Earth objects in that time.We will present results from the spectroscopy component of the MANOS program. Visible wavelength spectra are obtained using DeVeny on the Discovery Channel Telescope (DCT), Goodman on the Southern Astrophysical Research (SOAR) telescope, and GMOS on Gemini North and South. Over 300 NEO spectra have been obtained during our program. We will present preliminary results from our spectral sample. We will discuss the compositional diversity of the small NEO population and how the observed NEOs compare to the meteorite population.MANOS is funded by the NASA Near-Earth Object Observations program.

  17. An Island Coalescence Scenario for Near-Earth Current Disruption in the Magnetotail

    Institute of Scientific and Technical Information of China (English)

    MA Zhi-Wei; LU Xing-Qiang

    2009-01-01

    A current disruption and dipolarization scenario associated with island coalescences in the near-Earth region is proposed.The thin and elongated current-sheet built up during the growth phase is unstable due to a tearing mode instability that leads to formation of multiple magnetic islands (or magnetic flux ropes in the three dimensional case) in the near-Earth region.The growth rate of the tearing mode should be different in different locations because the rate is in general determined by the external driving force and the local plasma sheet properties.When the rate of the magnetic reconnection in the mid-tail region around 20 RE is much larger than that in other locations,the strong bulk earthward flows resulting from the fast reconnection in the mid-tail drive the earthward convection and the coalescence of the magnetic islands.Consequently,the cross-tail current in the near-Earth region is suddenly disrupted and the geometry of the magnetic field changes from tail-like to dipolar-like in the ideal time scale.This proposed scenario is tested by Hall MHD simulation and is compared with the observations.

  18. Defending Planet Earth: Near-Earth Object Surveys and Hazard Mitigation Strategies

    Science.gov (United States)

    2010-01-01

    The United States spends approximately four million dollars each year searching for near-Earth objects (NEOs). The objective is to detect those that may collide with Earth. The majority of this funding supports the operation of several observatories that scan the sky searching for NEOs. This, however, is insufficient in detecting the majority of NEOs that may present a tangible threat to humanity. A significantly smaller amount of funding supports ways to protect the Earth from such a potential collision or "mitigation." In 2005, a Congressional mandate called for NASA to detect 90 percent of NEOs with diameters of 140 meters of greater by 2020. Defending Planet Earth: Near-Earth Object Surveys and Hazard Mitigation Strategies identifies the need for detection of objects as small as 30 to 50 meters as these can be highly destructive. The book explores four main types of mitigation including civil defense, "slow push" or "pull" methods, kinetic impactors and nuclear explosions. It also asserts that responding effectively to hazards posed by NEOs requires national and international cooperation. Defending Planet Earth: Near-Earth Object Surveys and Hazard Mitigation Strategies is a useful guide for scientists, astronomers, policy makers and engineers.

  19. AcuA: the AKARI/IRC Mid-infrared Asteroid Survey

    CERN Document Server

    Usui, Fumihiko; Mueller, Thomas G; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; Ishihara, Daisuke; Kataza, Hirokazu; Takita, Satoshi; Oyabu, Shinki; Ueno, Munetaka; Matsuhara, Hideo; Onaka, Takashi

    2011-01-01

    We present the results of an unbiased asteroid survey in the mid-infrared wavelength with the Infrared Camera (IRC) onboard the Japanese infrared satellite AKARI. About 20% of the point source events recorded in the AKARI All-Sky Survey observations are not used for the IRC Point Source Catalog (IRC-PSC) in its production process because of the lack of multiple detection by position. Asteroids, which are moving objects on the celestial sphere, remain in these "residual events". We identify asteroids out of the residual events by matching them with the positions of known asteroids. For the identified asteroids, we calculate the size and albedo based on the Standard Thermal Model. Finally we have a brand-new catalog of asteroids, named the Asteroid Catalog Using Akari (AcuA), which contains 5,120 objects, about twice as many as the IRAS asteroid catalog. The catalog objects comprise 4,953 main belt asteroids, 58 near Earth asteroids, and 109 Jovian Trojan asteroids. The catalog will be publicly available via th...

  20. Asteroid Risk Assessment: A Probabilistic Approach.

    Science.gov (United States)

    Reinhardt, Jason C; Chen, Xi; Liu, Wenhao; Manchev, Petar; Paté-Cornell, M Elisabeth

    2016-02-01

    Following the 2013 Chelyabinsk event, the risks posed by asteroids attracted renewed interest, from both the scientific and policy-making communities. It reminded the world that impacts from near-Earth objects (NEOs), while rare, have the potential to cause great damage to cities and populations. Point estimates of the risk (such as mean numbers of casualties) have been proposed, but because of the low-probability, high-consequence nature of asteroid impacts, these averages provide limited actionable information. While more work is needed to further refine its input distributions (e.g., NEO diameters), the probabilistic model presented in this article allows a more complete evaluation of the risk of NEO impacts because the results are distributions that cover the range of potential casualties. This model is based on a modularized simulation that uses probabilistic inputs to estimate probabilistic risk metrics, including those of rare asteroid impacts. Illustrative results of this analysis are presented for a period of 100 years. As part of this demonstration, we assess the effectiveness of civil defense measures in mitigating the risk of human casualties. We find that they are likely to be beneficial but not a panacea. We also compute the probability-but not the consequences-of an impact with global effects ("cataclysm"). We conclude that there is a continued need for NEO observation, and for analyses of the feasibility and risk-reduction effectiveness of space missions designed to deflect or destroy asteroids that threaten the Earth. © 2015 Society for Risk Analysis.

  1. International CJMT-1 Workshop on Asteroidal Science

    Science.gov (United States)

    Ip, Wing-Huen

    2014-03-01

    An international workshop on asteroidal science was held between October 16 and 17, 2012, at the Macau University of Science and Technology gathering together experts on asteroidal study in China, Japan, Macao and Taiwan. For this reason, we have called it CJMT-1 Workshop. Though small in sizes, the asteroids orbiting mainly between the orbit of Mars and of Jupiter have important influence on the evolution of the planetary bodies. Topics ranging from killer asteroids to space resources are frequently mentioned in news reports with prominence similar to the search for water on Mars. This also means that the study of asteroids is very useful in exciting the imagination and interest in science of the general public. Several Asian countries have therefore developed long-term programs integrating ground-based observations and space exploration with Japan being the most advanced and ambitious as demonstrated by the very successful Hayabusa mission to asteroid 25143 Itokawa. In this volume we will find descriptions of the mission planning of Hayabusa II to the C-type near-Earth asteroid, 1999 JU3. Not to be outdone, China's Chang-E 2 spacecraft was re-routed to a flyby encounter with asteroid 4179 Toutatis in December 2012. It is planned that in the next CJMT workshop, we will have the opportunity to learn more about the in-depth data analysis of the Toutatis observations and the progress reports on the Hayabusa II mission which launch date is set to be July 2014. Last but not least, the presentations on the ground-based facilities as described in this volume will pave the way for coordinated observations of asteroidal families and Trojan asteroids - across Asia from Taiwan to Uzbekistan. Such international projects will serve as an important symbol of good will and peaceful cooperation among the key members of this group. Finally, I want to thank the Space Science Institute, Macao University of Science and Technology, for generous support, and its staff members

  2. A decision analysis approach for risk management of near-earth objects

    Science.gov (United States)

    Lee, Robert C.; Jones, Thomas D.; Chapman, Clark R.

    2014-10-01

    Risk management of near-Earth objects (NEOs; e.g., asteroids and comets) that can potentially impact Earth is an important issue that took on added urgency with the Chelyabinsk event of February 2013. Thousands of NEOs large enough to cause substantial damage are known to exist, although only a small fraction of these have the potential to impact Earth in the next few centuries. The probability and location of a NEO impact are subject to complex physics and great uncertainty, and consequences can range from minimal to devastating, depending upon the size of the NEO and location of impact. Deflecting a potential NEO impactor would be complex and expensive, and inter-agency and international cooperation would be necessary. Such deflection campaigns may be risky in themselves, and mission failure may result in unintended consequences. The benefits, risks, and costs of different potential NEO risk management strategies have not been compared in a systematic fashion. We present a decision analysis framework addressing this hazard. Decision analysis is the science of informing difficult decisions. It is inherently multi-disciplinary, especially with regard to managing catastrophic risks. Note that risk analysis clarifies the nature and magnitude of risks, whereas decision analysis guides rational risk management. Decision analysis can be used to inform strategic, policy, or resource allocation decisions. First, a problem is defined, including the decision situation and context. Second, objectives are defined, based upon what the different decision-makers and stakeholders (i.e., participants in the decision) value as important. Third, quantitative measures or scales for the objectives are determined. Fourth, alternative choices or strategies are defined. Fifth, the problem is then quantitatively modeled, including probabilistic risk analysis, and the alternatives are ranked in terms of how well they satisfy the objectives. Sixth, sensitivity analyses are performed in

  3. The NEOTωIST mission (Near-Earth Object Transfer of angular momentum spin test)

    Science.gov (United States)

    Drube, Line; Harris, Alan W.; Engel, Kilian; Falke, Albert; Johann, Ulrich; Eggl, Siegfried; Cano, Juan L.; Ávila, Javier Martín; Schwartz, Stephen R.; Michel, Patrick

    2016-10-01

    We present a concept for a kinetic impactor demonstration mission, which intends to change the spin rate of a previously-visited asteroid, in this case 25143 Itokawa. The mission would determine the efficiency of momentum transfer during an impact, and help mature the technology required for a kinetic impactor mission, both of which are important precursors for a future space mission to deflect an asteroid by collisional means in an emergency situation. Most demonstration mission concepts to date are based on changing an asteroid's heliocentric orbit and require a reconnaissance spacecraft to measure the very small orbital perturbation due to the impact. Our concept is a low-cost alternative, requiring only a single launch. Taking Itokawa as an example, an estimate of the order of magnitude of the change in the spin period, δP, with such a mission results in δP of 4 min (0.5%), which could be detectable by Earth-based observatories. Our preliminary study found that a mission concept in which an impactor produces a change in an asteroid's spin rate could provide valuable information for the assessment of the viability of the kinetic-impactor asteroid deflection concept. Furthermore, the data gained from the mission would be of great benefit for our understanding of the collisional evolution of asteroids and the physics behind crater and ejecta-cloud development.

  4. Small asteroid system evolution

    OpenAIRE

    Jacobson, Seth A.

    2014-01-01

    Observations with radar, photometric and direct imaging techniques have discovered that multiple asteroid systems can be divided clearly into a handful of different morphologies, and recently, the discovery of small unbound asteroid systems called asteroid pairs have revolutionized the study of small asteroid systems. Simultaneously, new theoretical advances have demonstrated that solar radiation dictates the evolution of small asteroids with strong implications for asteroid internal structur...

  5. Small asteroid system evolution

    OpenAIRE

    Jacobson, Seth A.

    2014-01-01

    Observations with radar, photometric and direct imaging techniques have discovered that multiple asteroid systems can be divided clearly into a handful of different morphologies, and recently, the discovery of small unbound asteroid systems called asteroid pairs have revolutionized the study of small asteroid systems. Simultaneously, new theoretical advances have demonstrated that solar radiation dictates the evolution of small asteroids with strong implications for asteroid internal structur...

  6. Search for Asteroid-Asteroid Encounters

    Directory of Open Access Journals (Sweden)

    Luis A. Mammana

    2001-01-01

    Full Text Available Earlier studies about asteroids did not consider mutual interactions since they assume a negligible asteroid mass. In 1966 Hertz took into account for the first time the gravitational effects produced by an asteroid on another for mass determination. This gravitational action becomes relevant for enough effective encounters. The most efficient gravitational interaction is that produced in a large time interval and for small distances. For each particular caseful it is relevant to perform a care analysis in order to determinate the feasibility in the mass determination and improved orbital elements. In the present paper we performed a search of asteroid-asteroid encounters occurred in the twenty century for the first 3000 numbered asteroids . Of all encounters we have selected only those asteroid pairs in which one of the asteroids has a diameter larger than 200 km and the other one (the smaller an observational interval of at least ten years.

  7. Earthward electric field and its reversal in the near-Earth current sheet

    Science.gov (United States)

    Artemyev, A. V.; Angelopoulos, V.; Runov, A.; Zelenyi, L. M.

    2016-11-01

    Using Time History of Events and Macroscale Interactions during Substorms observations (radial distance r from 9 to 35 Earth radii, RE), we investigate ion and electron contributions to the cross-tail current density in the magnetotail current sheet. We analyze plasma pressure measurements (including the contribution from high-energy particles) and estimate the magnitudes of ion and electron diamagnetic drifts. In the downtail, r > 15RE, region, ion (electron) diamagnetic drifts are shown to provide more than 50% (less than 25%) of the cross-tail current density at the neutral plane, Bx=0. Conversely, in the near-Earth region, r≤15RE, the ion (electron) diamagnetic drift contribution to the cross-tail current density is 20% (50%). The directly measured duskward (dawnward) component of the ion (electron) velocity, vyi (-vye), where y is the GSM direction, is very small (quite large) in the downtail region but large (small) in the near-Earth region. This systematic discrepancy between the expected values of vyi, -vye (based on estimates of diamagnetic drifts) and the direct measurements of the velocity, vyi, -vye, is consistent with a contribution to the total velocity by an E × B drift caused by an electric field oriented parallel to the x axis, Ex. To decrease the ion (increase the electron) total drift to agree with the measured flows in the downtail region and increase (decrease) this total drift to match the measurements in the near-Earth region, this Ex would need to be directed earthward at r > 15RE and tailward at r≤15RE. Such an Ex distribution is consistent with the equatorial projection of the Harang discontinuity.

  8. Analytical approach using KS elements to near-earth orbit predictions including drag

    Science.gov (United States)

    Sharma, Ram Krishnan

    1991-04-01

    An analytical theory for the motion of near-earth satellite orbits with the air drag effect is evolved in terms of the KS elements, using an analytical oblate exponential atmospheric density model. Due to the symmetry of the KS element equations, only one of the eight equations is integrated analytically to acquire the state vector at the close of each revolution. In the numerical studies performed, it is shown that after 100 revolutions, with a ballistic coefficient of 50, a maximum difference of 39 meters is found in the semimajor axis comparison for a very small eccentricity (0.001) instance having an initial perigee height of 391.425 km.

  9. First results from the rapid-response spectrophotometric characterization of Near-Earth objects using RATIR

    Science.gov (United States)

    Navarro-Meza, Samuel; Mommert, Michael; Reyes-Ruiz, Mauricio; Trilling, David E.; Butler, Nathaniel; Pichardo, Barbara; Moskovitz, Nicholas; Jedicke, Robert

    2016-10-01

    We are carrying out a program to obtain rapid-response spectrophotometric characterization of newly discovered Near Earth Objects. Our first results, based on observations made with WFCAM on UKIRT, are presented in Mommert et al. (2016). Here we present a preliminary analysis of the r-i distribution of ~140 small (work is part of a collaboration in which we will characterize hundreds of NEOs that are generally too faint for other characterization techniques (down to V~21). This work is supported by funding from NASA's Solar System Observations program.

  10. A comprehensive model of the quiet-time, near-Earth magnetic field: phase 3

    DEFF Research Database (Denmark)

    Sabaka, T.J.; Olsen, Nils; Langel, R.A.

    2002-01-01

    The near-Earth magnetic field is caused by sources in the Earth's core, ionosphere, magnetosphere, lithosphere and from coupling currents between the ionosphere and the magnetosphere, and between hemispheres. Traditionally, the main field (low degree internal field) and magnetospheric field have......, and includes an accounting for main field influences on the magnetosphere, main field and solar activity influences on the ionosphere, seasonal influences on the coupling currents, a priori characterization of the influence of the ionosphere and the magnetosphere on Earth-induced fields, and an explicit...

  11. Mini-satellite exploration of very near earth space fuel objects

    Energy Technology Data Exchange (ETDEWEB)

    Zuppero, A.C.; Jacox, M.G.

    1992-09-19

    A prospecting plan is presented to assay near Earth objects (NEO) for their potential to yield rocket fuel. The plan calls out small satellites as the near-term means to achieve low cost surveys and deep subsurface sampling of NEO composition. The water bearing classes of NEO to be considered are limited to those accessible in short time and with small thrusters. These include the water bearing clay objects (phylosilicates) at nearly trivial distances from Earth, and the recently identified water ice objects such as comet ({number_sign}4015) 1979 VA. These objects are evaluated as small satellite prospecting and assay vehicle targets.

  12. Mini-satellite exploration of very near earth space fuel objects

    Energy Technology Data Exchange (ETDEWEB)

    Zuppero, A.C.; Jacox, M.G.

    1992-09-19

    A prospecting plan is presented to assay near Earth objects (NEO) for their potential to yield rocket fuel. The plan calls out small satellites as the near-term means to achieve low cost surveys and deep subsurface sampling of NEO composition. The water bearing classes of NEO to be considered are limited to those accessible in short time and with small thrusters. These include the water bearing clay objects (phylosilicates) at nearly trivial distances from Earth, and the recently identified water ice objects such as comet ([number sign]4015) 1979 VA. These objects are evaluated as small satellite prospecting and assay vehicle targets.

  13. Adaptive Terminal Sliding Mode Control of Electromagnetic Spacecraft Formation Flying in Near-Earth